JP6940108B2 - Transparent touchpad - Google Patents

Description

The present invention relates to a transparent touch pad of a touch panel used as an input device for electronic devices such as mobile terminals, PCs, televisions, and in-vehicle displays.

A touch panel is a device that combines a display device such as a liquid crystal display device or an organic EL and a transparent touch pad that is a position input device. Input is performed to the device by touching the displayed screen part or moving a finger from the touched part. It is an input / output device installed in most of the mobile terminals currently in widespread use.

In the parts that make up the touch panel, a transparent touch pad is important along with the display device. The transparent touch pad is a device in which a component for position detection is arranged on a base material such as glass or transparent resin through which visible light is transmitted. As parts for position detection, there are those that detect the position by pressure and those that detect the position by the change of capacitance, but the one used in mobile terminals is the capacitance with fast response speed. The one that detects the position with is the mainstream.

Surface type and projection type are known as transparent touchpads of the type that detects the position by capacitance. The surface type is a type in which voltages are applied to the four corners of the screen and the positions on the screen are detected by changes in the capacitance at the four corners. On the other hand, in the projection type, wiring is arranged vertically and horizontally on the screen, and a portion where the capacitance changes in the vertical direction and the horizontal direction is detected.

The surface type has a simple structure and has the advantage that it can be used even on a large screen. However, only one point on the screen can be detected at a time (single touch). On the other hand, the projection type has a complicated structure, but it is possible to detect the position of multiple points at once (multi-touch).

Projective transparent touchpads must have wiring placed across the screen. Therefore, a transparent and conductive material is required. Conventionally, as a transparent conductive material, ITO (Indium Tin Oxide: indium tin oxide), ZnO (zinc oxide) -based material, and TiO ₂ (titanium oxide) -based material are known. At present, ITO, which has a proven track record in manufacturing technology and production volume, is mainly used as a transparent conductive material.

However, since ITO is produced by a film forming process in vacuum, it is costly in the equipment and manufacturing process. Moreover, the conductivity of ITO is not high at all. Therefore, when ITO is used for a large screen, it takes time to detect it. As a result, there is a technical problem that the reaction is delayed and a malfunction occurs due to noise.

Further, in the manufacturing process, annealing at a high temperature is required in order to exhibit transparency and conductivity. Therefore, there is a restriction that the materials that can be used as the substrate are limited. Further, since ITO is a ceramic-based material, it lacks flexibility. Therefore, there is a restriction that it cannot be used for a bent or bent portion that requires flexibility. Therefore, a transparent conductive material or a transparent structural wiring that replaces ITO is being studied.

The transparent structure wiring is to form invisible wiring by thinning the wiring. Normally, with the naked eye, 50 μm is said to be the detection limit. Therefore, the idea that wiring thinner than this can be treated as almost transparent is the basis of this technology.

The thin wiring itself can be formed with a submicron thickness by semiconductor technology. However, there is a demand for a method having a line width of several μm to several tens of μm, or submicron order, which is higher in conductivity (lower resistivity) than ITO and can be manufactured at a lower cost.

Patent Document 1 discloses a technique using a transparent electrode and a metal auxiliary wire having a line width that cannot be confirmed with the naked eye. This does not replace ITO at once, but partially uses metal wiring with a line width that cannot be seen with the naked eye. Here, it is said that if the line width is 30 μm or less, it cannot be visually recognized. The metal auxiliary wire is manufactured by a vacuum film forming technique and is formed by a photolithography technique.

Patent Document 2 discloses a technique in which an electrolytic copper foil or a rolled copper foil is processed into a fine pattern and used because the vacuum-formed metal film is not preferable because of stress. Here, a copper foil pattern having a width of 7 μm and a pitch of 300 μm is disclosed. That is, in the pattern in which the copper foil having a width of 7 μm is formed every 300 μm, the portion without the copper foil (which is used as the opening) is larger than the line width, so that light can pass through and the pattern is used as a transparent structural wiring. be able to.

Further, the touch pad requires electrodes in the x-direction and the y-direction. Therefore, as a method for reducing the man-hours in manufacturing, Patent Document 3 discloses a technique for manufacturing a circuit by simultaneous exposure on both sides of a base material having a UV cut function.

International Publication No. 2011/111650 (Patent No. 5503729) Japanese Unexamined Patent Publication No. 2015-157392 Patent No. 6042486

According to the technique disclosed in Patent Document 1, it is said that a metal auxiliary wiring having an invisible line width can be obtained, but it does not completely replace the transparent electrode conventionally used.

In Patent Document 2, since the copper of the wiring pattern is not formed by vacuum film formation, it can be said that the stress problem of the film is improved. However, after the electrolytic copper foil is transferred to the substrate, the wiring pattern is formed by using a photolithography technique. Therefore, it can be said that the manufacturing man-hours are still large.

Patent Document 3 discloses a technique for forming an electrode in the x direction and an electrode in the y direction on the front and back surfaces of one substrate at a time. This method is preferable because the man-hours are shortened. However, since the conductive layer uses vacuum film formation technology such as sputtering and thin film deposition, there are problems such as stress remaining in the film, variation in film thickness depending on the location of the substrate, and increase in resistivity due to the formation of voids in the film. Remain.

In particular, in a touch pad that is required to be flexible in the future, if internal stress remains in the conductive layer, there is a risk of disconnection due to film peeling when bent.

The present invention has been conceived in view of the above problems, and the x-direction and y-direction electrodes required for the touchpad can be manufactured with a small number of man-hours, and even if the touchpad itself is bent, a failure such as disconnection occurs. It provides a touchpad with a difficult structure. In the transparent touch pad according to the present invention, a groove forming a wiring is formed by a transparent photoresist, and a metal layer is formed in the groove by electroless plating.

More specifically, the transparent touch pad according to the present invention includes a transparent substrate containing an ultraviolet absorber and a transparent substrate.
A groove structure formed of a transparent photoresist on both sides of the transparent substrate via a plating catalyst layer,
Have a metal layer disposed in the groove structure,
The transparent photoresist contains at least one of an ultraviolet absorber and a radical scavenger .

The transparent touch pad according to the present invention contains a UV absorber and forms a groove structure with a transparent photoresist on a transparent substrate having an ultraviolet absorbing ability (a characteristic that ultraviolet rays do not pass through the transparent substrate), and the groove structure is formed in the groove. A conductive layer is formed by electroless plating. Therefore, since it is a conductive layer made by plating, it is possible to form a dense wiring having a small resistivity without voids.

Further, since the ultraviolet rays for exposure emitted from one surface of the transparent substrate do not reach the other surface, the front surface and the back surface of the transparent substrate can be aligned and exposed at the same time, which reduces the manufacturing cost. It can be reduced.

Further, since the conductive metal layer is formed in the groove formed by the transparent photoresist, it is difficult to peel off and cut. Therefore, even if the transparent substrate is bent and stretched, an accident such as disconnection is unlikely to occur.

It is a figure which shows the cross-sectional structure of the transparent touch pad which concerns on this invention. It is a perspective view of FIG. It is a figure which shows the state which formed the plating catalyst layer on the transparent electrode in the manufacturing process of the transparent touch pad which concerns on this invention. It is a figure which shows the state which formed the transparent photoresist in the manufacturing process of the transparent touch pad which concerns on this invention. It is a figure which shows the state of exposing the transparent photoresist in the manufacturing process of the transparent touch pad which concerns on this invention. It is a figure which shows the state which formed the groove structure by removing the uncured portion of the transparent photoresist in the manufacturing process of the transparent touch pad which concerns on this invention. It is a figure which shows the state which formed the metal layer in the groove structure in the manufacturing process of the transparent touch pad which concerns on this invention. It is a figure which shows the state which formed the protective layer and the sealing layer on the whole surface of the front and back sides in the metal layer formed in the groove structure in the manufacturing process of the transparent touch pad which concerns on this invention. It is a figure which shows the structural example of the wiring pattern provided in the transparent touch pad of this invention. It is a figure which shows the structure of the electronic device which carries the touch panel using the transparent touch pad of this invention.

The transparent touch pad according to the present invention will be described below with reference to drawings and examples. The following description exemplifies one embodiment and one embodiment of the present invention, and the present invention is not limited to the following description. The following description can be modified without departing from the spirit of the present invention.

FIG. 1 shows the cross-sectional structure of the transparent touch pad according to the present invention. FIG. 2 is a perspective view of FIG. In the transparent touch pad 1, a groove structure 14 formed of a transparent photoresist 14r is formed on the front surface 10a and the back surface 10b of the transparent substrate 10, and a metal layer 16 is arranged in the groove structure 14. The wiring 18 is formed by the groove structure 14 and the metal layer 16. As will be described later, in the transparent touch pad 1 according to the present invention, the metal layer 16 is formed by a plating method. Therefore, the plating catalyst layer 12 is arranged on the surface 10a of the transparent substrate 10, including between the transparent photoresist 14r and the transparent substrate 10.

Note that FIG. 1 shows a state in which the surface 10a side of the transparent substrate 10 is viewed in a cross section perpendicular to the traveling direction of the groove structure 14. Further, the back surface 10b side shows a part of a cross section parallel to the traveling direction of the groove structure 14. It is a cross section AA of FIG. Here, the front surface 10a and the back surface 10b are only distinguished for explanation, and there is no structural difference. However, in the following description, the surface facing the flat display will be the back surface 10b.

It is desirable that the transparent substrate 10 allows sufficient visible light to pass through and is not cloudy. This is because the touch pad is mounted on a flat display such as a liquid crystal display and used, so that the light from the flat display can pass through as much as possible. Desirably, the haze is 4% or less.

Further, the transparent substrate 10 has an ultraviolet absorbing ability. This is so that the front surface 10a and the back surface 10b of the transparent substrate 10 can be exposed at the same time. Since ultraviolet light having a wavelength of 365 nm is usually used for exposure to ultraviolet rays, it is desirable that the absorption of this wavelength is 90% or more, preferably 95% or more, between the front surface 10a and the back surface 10b. Of course, visible light is transmitted as much as possible.

In order to impart the ultraviolet absorbing ability to the transparent substrate 10, the ultraviolet absorber is dispersed in the transparent substrate 10. As the ultraviolet absorber, inorganic substances such as zinc oxide, titanium oxide and alumina, and aromatic organic substances such as diethylaminohydroxybenzoyl benzoate xyl, t-butylmethoxydibenzoylmethane, ethylhexyl methoxycinnamate and oxybenzone can be preferably used.

Further, the transparent substrate 10 needs to have little color unevenness. This is because, as a touch panel, color unevenness does not occur in the display light emission. In order to realize this, it is desirable that the retardation of the transparent substrate 10 is 10 nm or less. This is because if the retardation is small, birefringence can be ignored as with glass.

Further, it is desirable that the transparent substrate 10 has flexibility. In recent years, flat displays that can be bent (flexible) have appeared. Therefore, it is desirable that the transparent touch pad 1 can also be bent following the flat display. As such a transparent substrate 10, an acrylic resin can be most effectively used.

Further, in order to enhance the flexibility of the transparent substrate 10, the transparent substrate 10 may contain a core-shell rubber to the extent that the transparency is not hindered. The core-shell rubber is a rubber particle having a size of about several tens of nm. By mixing these, the strength of the base material can be improved.

The groove structure 14 is formed by a transparent photoresist 14r. In the transparent photoresist 14r, the exposed and cured portion is used as a component of the component until later. Therefore, it is desirable that the transparent photoresist 14r has a transparency and a haze value that does not easily change over time even after being cured to form the groove structure 14.

Further, the transparent photoresist 14r also needs to be less likely to cause color unevenness. This is because the transparent photoresist 14r also covers most of the transparent substrate 10. Therefore, it is desirable to have the same retardation characteristics as the transparent substrate 10.

Further, the transparent photoresist 14r is a remaining member as the groove structure 14. Therefore, there is a risk of deterioration and yellowing due to ultraviolet rays from the outside due to sunlight and ultraviolet rays from a light emitting portion such as a flat display from the inside. Therefore, the transparent photoresist 14r may contain an ultraviolet absorber or a radical scavenger.

Here, as the ultraviolet absorber, known materials such as benzotriazole-based, triazine-based, and benzophenone-based materials can be used. Further, as the light stabilizer, a hindered amine-based photostabilizer (HALS), a phenol-based antioxidant, and an aromatic amine-based antioxidant can be preferably used.

These ultraviolet absorbers and radical scavengers may be contained in an amount of 0.3 to 0.6% by mass based on the entire resin. The ultraviolet absorber and the radical scavenger may be mixed and used. It is known that the stability to light is synergistically improved by using a mixture of an ultraviolet absorber and a radical scavenger. Adding an ultraviolet absorber or a radical scavenger to a transparent photoresist in this way may be referred to as imparting light stability.

Regarding the color unevenness of the transparent substrate 10 and the transparent photoresist 14r, it is sufficient that the color unevenness does not occur in the completed state as the transparent touch pad. The transparent photoresist 14r includes a transparent photoresist using a polyimide resin and one using an epoxy resin, but it is preferable to use a transparent photoresist using an epoxy resin or an acrylic resin. This is because the retardation can be reduced.

The metal layer 16 is arranged in the groove structure 14. In the transparent touch pad 1 according to the present invention, the metal layer 16 is formed by a plating method. This is because a dense metal layer can be formed and the resistivity can be reduced to a value similar to that of bulk. As the metal, a conductive metal is used, and conductive metals such as gold, silver, copper, iron, tin, aluminum and nickel, and alloys containing these elements can be preferably used.

Since the transparent touch pad 1 is made of a resin material that can be said to be non-conductive, an electroless plating method is used to form the metal layer 16. Therefore, the plating catalyst layer 12 is arranged on the front surface 10a and the back surface 10b of the transparent substrate 10. That is, the plating catalyst layer 12 remains between the transparent photoresist 14r and the transparent substrate 10. The plating catalyst layer 12 is preferably formed of a metal substance containing Pd, Ni, Pt, Cu and the like, or a polymer member impregnated with these substances.

The plating catalyst layer 12 needs to have a sufficiently low conductivity. This is because the plating catalyst layer 12 continues to exist on the entire surface of the transparent substrate 10, and if the conductivity is high, all the wiring patterns formed by the groove structure 14 are in a conductive state. Therefore, the plating catalyst layer 12 can be called an insulating layer. Further, the plating catalyst layer 12 also needs to be formed sufficiently thin. This is because the metal substance used for the plating catalyst layer 12 basically does not transmit light, and if the plating catalyst layer 12 is formed thick, the transparency of the transparent touch pad 1 is lowered.

Further, an adhesion auxiliary agent such as a silane coupling agent may be applied between the transparent substrate 10 and the plating catalyst layer 12. Since the transparent substrate 10 is a resin, its surface is covered with hydrophobic groups. Therefore, the metal particles constituting the plating catalyst layer 12 may be difficult to bind.

See FIG. In addition to the metal layer 16 formed of the groove structure 14, the transparent touch pad 1 may be formed with a wide metal layer 16G that can also be used as a feeder line. The width 16w of the metal layer 16 is about 1 to 3 μm, whereas the width 16Gw of the metal layer 16G has a width of about 80 to 200 μm. In the transparent touch pad 1 according to the present invention, since the metal layer 16 and the metal layer 16G are formed by plating, the metal layers 16 having different thicknesses can be formed on the same plane at the same time.

The pitch 16p between the metal layers 16 is about 100 to 500 μm. If the metal layers 16 are provided at such intervals, it becomes difficult to visually recognize them, and they appear transparent to the naked eye. The metal layer 16G may be visible to the naked eye. This is because the metal layer 16G is assembled so as to be hidden and invisible when manufactured as a touch panel.

Next, a method for manufacturing the transparent touch pad 1 according to the present invention will be described. See FIG. A plating catalyst layer 12 is applied to both surfaces (front surface 10a, back surface 10b) of the transparent substrate 10 containing an ultraviolet absorber. The method for forming the plating catalyst layer 12 is not particularly limited. Vacuum treatment such as sputtering or vapor deposition may be performed, or the plating catalyst layer 12 may be formed by applying a coating material containing a metal serving as a plating catalyst to the transparent substrate 10. The plating catalyst layer 12 is applied to both the front surface 10a and the back surface 10b of the transparent substrate 10.

Next, with reference to FIG. 4, the transparent photoresist 14r is formed in layers on both surfaces of the transparent substrate 10. This can be formed by applying a liquid transparent photoresist 14r. The transparent photoresist 14r can be used in either the negative type or the positive type. Hereinafter, the description will be continued as a negative type (exposed portion remains) transparent photoresist 14r.

Next, referring to FIG. 5, the mask 20a and the mask 20b having the groove pattern formed are arranged and exposed on the outside of the transparent photoresist 14r (the side far from the thickness center of the transparent substrate 10). The mask 20a and the mask 20b are masks for the groove patterns of the front surface 10a and the back surface 10b of the transparent substrate 10, respectively. If the wiring directions of the metal layer 16 are different between the front surface 10a and the back surface 10b, it can be said that the groove structure 14 is different between the front surface 10a and the back surface 10b.

Here, since the transparent substrate 10 contains an ultraviolet absorber, the ultraviolet UVu irradiated from the front surface 10a side does not reach the back surface 10b. Further, the ultraviolet UVd irradiated from the back surface 10b side does not reach the front surface 10a. Therefore, even if ultraviolet rays are simultaneously irradiated from both sides of the transparent substrate 10, the groove patterns on the front surface 10a and the back surface 10b can be formed without being interfered by the ultraviolet rays emitted from the opposite sides.

With reference to FIG. 6, the exposed transparent photoresist 14r is developed to form a groove structure 14. Here, the plating catalyst layer 12 formed on the front surface 10a and the back surface 10b of the transparent substrate 10 is exposed at the bottom of the formed groove structure 14. Next, the transparent substrate 10 is electrolessly plated to form a metal layer 16 in the groove structure 14 to form a wiring 18 (FIG. 7). Before forming the metal layer 16, a Ni-based metal may be electroless plated on the plating catalyst layer 12, and then the metal layer 16 may be electrolessly or electroless plated.

In the transparent touch pad 1 according to the present invention, since the metal layer 16 is formed by the plating method, the metal layer 16 having a uniform thickness can be formed even if the metal layer 16 has portions having different widths. The wiring 18 of the transparent touch pad 1 can be formed by the metal layer 16 arranged in the groove structure 14 in this way. The metal layer 16 formed by electroplating may be further formed directly above the metal layer 16 formed by electroless plating.

See FIG. A protective layer 30 may be formed on the metal layer 16. The protective layer 30 includes a blackening layer, a rust preventive layer, and the like. Further, the sealing layer 32 may be arranged on the transparent photoresist 14r with only the metal layer 16 or the protective layer 30 and the metal layer 16 formed so that the transparent photoresist 14r does not come into contact with the outside air. .. A transparent resin such as an acrylic resin is used for the sealing layer 32. Further, the sealing layer 32 can be impregnated with an ultraviolet absorber to impart an ultraviolet absorbing ability.

Although the transparent photoresist 14r was cured by exposure, it may deteriorate and discolor if it is constantly irradiated with ultraviolet rays. More specifically, the front surface 10a side is exposed to sunlight from the outside, and the back surface 10b is exposed to ultraviolet rays from the display. Therefore, it has been shown above that the transparent resist 14r may be mixed with an ultraviolet absorber or a radical scavenger. However, in order to further extend the life of the transparent touch pad 1, the sealing layer 32 provided on at least one of the back surface 10b and the front surface 10a contains an ultraviolet absorber to suppress deterioration of the transparent photoresist 14r from light (ultraviolet rays). You may try to do it. This can be said to give the sealing layer 32 an ultraviolet absorbing ability.

Further, a radical scavenger may be mixed in the closed layer 32. This is because, as described above, the coexistence of the ultraviolet absorber and the radical scavenger enhances the absorption of light and the durability against light. As the ultraviolet absorber and the radical scavenger, the same ones used for the transparent resist 14r can be used. Further, imparting the light stabilizing ability to the transparent resist 14r and imparting the ultraviolet absorbing ability to the sealing layer 32 may be carried out at the same time, or only one of them may be carried out.

Next, FIG. 9 shows an example of the formation pattern of the wiring 18 on the transparent touch pad 1. The wiring pattern 25 is formed by feeding lines 25S in which mesh-shaped wirings 18 are provided in strip-shaped regions 25A on the front surface 10a and back surface 10b of the transparent substrate 10 and electrodes are attached to each strip-shaped regions 25A. The portion of the wiring 18 and the feeder line 25S can also be formed by the method described with reference to FIG.

Further, in the wiring pattern 25, in order to detect the touched position, the wiring pattern 25y for the Y-axis and the wiring pattern 25x for the X-axis are arranged without contacting each other. In the case of the transparent touch pad 1 of the present invention, the X-axis wiring pattern 25x and the Y-axis wiring pattern 25y are formed on the front surface 10a and the back surface 10b of the transparent substrate 10. Therefore, the wiring patterns for the X-axis and the Y-axis do not overlap on the same plane.

FIG. 10 shows a configuration of an electronic device having a touch panel 43 in which the transparent touch pad 1 according to the present invention is arranged on a display device (flat display) 43a such as a liquid crystal display or an organic EL. In FIG. 10, the transparent touch pad 1 is indicated by reference numeral 43b. As a specific wiring pattern of the transparent touch pad 1 (43b), the wiring pattern 25 shown in FIG. 8 can be used.

A control device 42 is connected to the touch panel 43, and a communication device 45 is further connected to the control device 42. Further, a camera 46 and a speaker 47 may be provided. The electronic device 40 having such a configuration can be used as a mobile terminal or a control terminal for the device. The transparent touch pad 1 according to the present invention can be suitably used for such an electronic device 40.

The touch panel 43 operates as an input / output device. The content displayed from the control device 42 is input through the touch panel 43. The communication device 45 may be wireless or wired. Further, the communication connection may be made so that it can be connected not only to individual terminals but also to a public line.

The camera 46 inputs an external image, converts it into a signal, and passes it to the control device 42. The control device 42 performs processing such as accumulating, processing, and transmitting the obtained image signal. Further, the speaker 47 may be a microphone. The speaker 47 outputs an audio signal. Further, when it is used as a microphone, it is possible to take in an external sound as a signal and perform processing such as storage, processing, and transmission.

In addition, the electronic device 40 can realize various functions depending on the software installed in the electronic device 40.

Further, the electronic device 41 may have a form in which the operating unit 48 is connected to the control device 42 of FIG. The operating unit 48 may be connected to a sensor or the like, or may be connected to a motor, an internal combustion engine, a battery to be controlled, or the like for performing mechanical operation. As described above, the transparent touch pad 1 according to the present invention can be mounted on the electronic devices 40 and 41 and used.

The transparent touch pad 1 according to the present invention, in a completed state as a touch pad, has a transmittance of 91% or more in the visible light region, a haze value of 2% or less, a retardation of 10 nm or less, and is bent with a radius of 1 mm. However, it is desirable that the conductive state is maintained.

Here, "bending" means that any portion of the wiring 18 (which may be referred to as a metal layer 16) is bent, and the radius R of the bent portion is 1 mm. It should be noted that the transparent touch pad 1 may have at least one place where continuity is maintained even when bent, and it is not necessary that continuity is ensured even when bent at an arbitrary part.

The transparent substrate 10 was made of an acrylic resin containing an ultraviolet absorber and had a low retardation. The thickness was 50 μm. Palladium particles were formed into a plating catalyst layer 12 to a thickness of 30 nm on both sides of the transparent substrate 10 by a slit coating method.

As the transparent photoresist 14r, ATN 1021 negative type acrylic resist manufactured by Dow Chemical Co., Ltd. was used. The transparent photoresist 14r layer was formed on both sides of the transparent substrate 10 so that the thickness after drying was 1.5 μm. Even in the state where the transparent photoresist 14r layer was formed, there was almost no change in the optical characteristics.

Wiring pattern masks in the x-direction and the y-direction were arranged on the front surface 10a and the back surface 10b of the transparent substrate 10, respectively. In the groove pattern, the width of the narrowest groove is 2 μm. A groove having such a width cannot be visually discriminated even if the groove structure 14 does not allow light to pass through. As a result, even if it is wired on the transparent substrate 10, it is recognized as transparent.

The groove patterns on the front surface 10a and the back surface 10b were simultaneously exposed to ultraviolet light having a wavelength of 365 nm. Next, this was developed with a strong alkaline developer, and the unexposed portion was removed to form a groove structure 14 to form a metal layer 16. The plating catalyst layer 12 is exposed at the bottom of the groove. The pattern of the groove structure 14 was different between the front surface 10a and the back surface 10b of the transparent substrate 10, but there was no particular interference, and each groove pattern was formed on both the front surface 10a and the back surface 10b.

Next, the transparent substrate 10 was subjected to electroless copper plating using CIRPUPOSIT 4500 manufactured by Dow Chemical Co., Ltd. to form copper in the groove structure 14 to a thickness of 1.5 μm. The transparent substrate 10 on which the metal layer 16 was formed could not visually recognize the wiring pattern 25. Protective layers of acrylic resin were formed on both sides of the transparent substrate 10 to a thickness of 1 μm to obtain the transparent touch pad 1 of the present invention.

The transparent touch pad 1 had a transmittance of 92% in the visible light region, a haze value of 1.7%, and a retardation of 4 nm. In addition, a bending test with a radius of 1 mm was performed, but there was no disconnection and no problem occurred in the conduction state.

As described above, in the transparent touch pad 1 according to the present invention, the plating catalyst layer 12 is formed on the entire surface of the transparent substrate 10 having an ultraviolet absorber, and the transparent photoresist 14r is applied to the entire surface, and the front surface 10a and the back surface 10b are coated. Since both sides of the above are simultaneously exposed to form a groove and a wiring provided with the metal layer 16 is created, the manufacturing man-hours are small. In addition, all production can be done in the atmosphere and does not include high temperature processes such as thermal firing. Therefore, the configuration is such that the cost can be reduced.

The present invention can be suitably used for a touch panel used for a mobile terminal, and can also be used for a PC, a television, an in-vehicle terminal, a signage (electronic signage), an electronic board, a heater wiring, an electromagnetic wave shield, and the like. Further, it can also be suitably used in a circuit board provided on a non-transparent substrate.

1 Transparent touch pad 10 Transparent substrate 10a Front surface 10b Back surface 12 Plating catalyst layer 14 Groove structure 14r Transparent photoresist 16 Metal layer 18 Wiring 20a Mask 20b Mask 25 Wiring pattern 25x Wiring pattern for X-axis 25y Wiring pattern for Y-axis 30 Protection Layer 32 Sealed layer 40, 41 Electronic equipment 43 Touch panel 43a Display device 42 Control device 45 Communication device 46 Camera 47 Speaker

Claims (1)

A transparent substrate containing an ultraviolet absorber and
A groove structure formed of a transparent photoresist on both sides of the transparent substrate via a plating catalyst layer,
Have a metal layer disposed in the groove structure,
A transparent touch pad characterized in that at least one of an ultraviolet absorber and a radical scavenger is contained in the transparent photoresist.

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