JP2021077244A - Touch pad, touch panel and method for producing the same and electronic apparatus including the same - Google Patents

Abstract

To provide a transparent touch pad that prevents the strength of six-sides tempered glass from deteriorating.SOLUTION: A transparent touch panel 10 has six-sides tempered glass 12, a groove structure formed of a transparent photoresist on one side of the six-sides tempered glass 12 through plating catalyst layers 14, 20, and electrode layers (first electrode layer 16 and second electrode layer 22) disposed in the groove structure and constituted by metal layers. The transparent photoresist contains at least one of ultraviolet absorber or radical scavenger.SELECTED DRAWING: Figure 1

Description

The present invention relates to a touch pad of a touch panel used as an input device for an electronic device such as a mobile terminal, a PC, a television, or an in-vehicle display, a touch panel, a manufacturing method thereof, and an electronic device using the touch pad.

A touch panel is a device that combines a display device such as a liquid crystal display device or an organic EL with a transparent touch pad that is a position input device. Input 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.

Conventionally, this transparent touch pad is a transparent electrode using ITO (Indium Tin Oxide), ZnO (zinc oxide) material or TiO ₂ (titanium oxide) material, and forms sensors in the X and Y directions. And this was pasted on the display device. However, since such a transparent touchpad requires many manufacturing processes, a one-glass solution (OGS) that incorporates a touchpad function into the cover glass of an electronic device has been proposed. There is.

In this OGS, since the touch pad function is incorporated in the cover glass of the electronic device, the touch pad function does not operate due to the breakage of the cover glass. That is, even if the cover glass is damaged, it is necessary to increase the strength of the cover glass as compared with the conventional electric device capable of touch operation.

As for the strengthening of the cover glass, an ion exchange strengthening method (chemical strengthening method) for glass has been proposed. By immersing the glass in a molten salt below the glass transition point, the alkaline ions inside the glass are exchanged for alkaline ions with a larger ionic radius, and compressive stress is generated on the glass surface due to the difference in ionic radius. The method.

The cover glass by the chemical strengthening method may be hardened and then cut to a desired size, or the unstrengthened glass may be cut to a desired size and then strengthened. When cut after strengthening, the strengthened surface becomes two surfaces, the front surface and the back surface (two-sided tempered glass), and the cut surfaces on all sides become non-reinforced surfaces. If it is strengthened after cutting, the cut surfaces on all sides will also be strengthened surfaces (6-sided tempered glass).

Chemically strengthened glass has higher impact resistance and is less likely to break than ordinary glass. However, this strength is reduced by exposure to constant heat treatment. When manufacturing a touch panel, there are many steps that are usually exposed to high-temperature annealing for forming ITO and heat treatment such as exposure to plasma when forming a conductive wire by sputtering or the like.

Therefore, in Patent Document 1, a cured film is formed between a glass that has been strengthened using a curable composition containing a compound having an organic group and a siloxane bond and a transparent conductive film formed on one surface of the glass. A method of suppressing a decrease in surface strength due to the formation of a transparent conductive film of a strengthened glass by forming the glass is disclosed.

Further, in Patent Document 2, a chemically strengthened glass substrate with a transparent conductive film is formed by chemically strengthening a glass substrate to form a chemically strengthened glass substrate and forming a transparent conductive film on the chemically strengthened glass substrate. The chemically strengthened glass substrate with a transparent conductive film contains 2 to 7% Na2O and 0 to 3% Li2O in terms of mass%, has a strain point of 550 ° C. or higher, and has a surface compressive stress of 200 to 800 MPa. A chemically strengthened glass substrate with a transparent conductive film is disclosed.

Japanese Unexamined Patent Publication No. 2016-124720 Japanese Unexamined Patent Publication No. 2004-131314

A transparent electrode material such as ITO has a relatively high electrical resistance, and there is a problem that the reaction speed decreases as the area of the touch panel increases. Therefore, in view of the problem of reducing the strength of the chemically strengthened glass, it is desirable to use a thin metal wire as the electrode material.

However, when the thin metal wire is formed by a vacuum film forming method such as sputtering, there is a problem that the chemically strengthened glass is exposed to plasma and the strength is lowered.

The present invention has been conceived in view of the above problems, and provides a transparent touch pad having an OGS structure that is not easily damaged, a touch panel using the transparent touch pad, a manufacturing method thereof, and an electronic device using the touch panel. ..

More specifically, the transparent touch pad according to the present invention is
Six-sided tempered glass and
On one side of the six-sided tempered glass,
A groove structure formed of a transparent photoresist via a plating catalyst layer,
It has an electrode layer composed of a metal layer arranged in the groove structure, and has an electrode layer.
The transparent photoresist contains at least one of an ultraviolet absorber and a radical scavenger.

Further, the touch panel according to the present invention is
The display device is adhered to the side of the transparent touch pad described above on which the electrode layer is arranged via optical glue.

Further, the electronic device according to the present invention is
It is characterized by using the above touch panel.

Further, the method for manufacturing a transparent touch pad according to the present invention is as follows.
The process of forming a plating catalyst layer on one surface of six-sided tempered glass,
A step of forming a grooved transparent photoresist layer having a groove structure in which the plating catalyst layer is exposed on the bottom surface on the upper surface of the plating catalyst layer.
It is characterized by having a step of electroless plating the six-sided tempered glass to form a metal layer in the groove structure.

In the transparent touch pad according to the present invention, the surface of the metal layer formed on the six-sided tempered glass can be formed smoothly because the portion where the metal layer is not formed is filled with the transparent photoresist. , There is no unevenness in adhesion to the display device.

Further, since this configuration is not exposed to heat treatment such that the temperature of the 6-sided tempered glass becomes 100 ° C. or higher, it can be used without lowering the strength of the 6-sided tempered glass.

It is a figure which shows the structure of the transparent touch pad which concerns on this invention. It is a partial cross-sectional view of the transparent touch pad which concerns on this invention. It is a figure which shows the manufacturing process of the transparent touch pad which concerns on this invention. It is a figure which shows the manufacturing process of the transparent touch pad which concerns on this invention. It is a figure which shows the structure of the touch panel which concerns on this invention. It is a partial sectional view of the touch panel which concerns on this invention. It is a figure which shows the structure of the communication terminal and the electronic device equipped with the touch panel which used the transparent touch pad of this invention.

The transparent touch pad, the touch panel, and the electronic device 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 configuration of the transparent touch pad 10 according to the present invention. The transparent touch pad 10 has a structure in which the electrode portion 13 is formed on one surface of the six-sided tempered glass 12. The electrode structure 13 is composed of a plating catalyst layer 14, a first electrode layer 16, an intermediate layer 18, a plating catalyst layer 20, and a second electrode layer 22 from a layer close to the six-sided tempered glass.

FIG. 2 shows a part of the AA cross section of FIG. The six-sided tempered glass 12 is a chemically tempered glass. For example, by putting soda-lime glass cut into a predetermined size in a molten salt of potassium nitrate at 380 ° C. and replacing Na ions on the glass surface with Ka ions, a chemically strengthened glass resistant to impact can be obtained.

The process of strengthening glass in this way is called a glass strengthening process. Since the six-sided tempered glass is formed into a size to be used in advance and then subjected to the strengthening process, the strengthening process is performed on all six sides. As a result, the impact strength becomes very strong.

The plating catalyst layer 14 is preferably formed of a metal substance containing Pd, Ni, Pt, Cu and the like, or a polymer member impregnated with these substances. However, these metallic substances are not light transmissive. Therefore, the plating catalyst layer 14 is formed sufficiently thin so that the light transmittance of the transparent touch pad 10 does not decrease. Specifically, the plating catalyst layer 14 can be formed with a thickness of about 30 nm so that there is no problem in practical use.

Here, "there is no problem in practical use" means that the transparency of the transparent touch pad 10 can be ensured, and the metal layer 16 m and the metal layer 22 m, which will be described later, can be formed by electroless plating.

The first electrode layer 16 is an electrode of the transparent touch pad 10 in the X or Y direction. Here, the first electrode layer 16 is assumed to be an X-direction electrode, and the second electrode layer 22 is a Y-direction electrode. With reference to FIG. 1 again, the first electrode layer 16 is composed of a sensing line 16a extending in the X direction and an address line 16b in the X direction connected to each sensing line 16a.

Here, although two electrode layers are used and the address lines are separately provided in the X direction and the Y direction, the electrode layer is not limited to the two layers, and the X direction and the X direction are included in one layer. The configuration may be such that the address lines in the Y direction are integrated, or a configuration in which a third electrode layer is separately provided may be used.

Each sensing line 16a is composed of a plurality of conduction lines 15. The conductive wire 15 has a line width of about 1 to 5 μm. This is because with this width, it looks transparent because it is almost invisible to the naked eye.

On the other hand, the X-direction address line 16b may be a line thicker than the conduction line 15. This is because the X-direction address line 16b is formed on the edge of the transparent touch pad 10 and is arranged at a position invisible to the user.

See FIG. 2 again. The first electrode layer 16 is formed by filling the groove structure 16c of the transparent photoresist 16r formed on the plating catalyst layer 14 with a metal layer 16m. The metal layer 16m filled in the groove structure 16c can be called a conduction wire 15. The first electrode layer 16 in FIG. 2 represents a cut surface cut along a surface perpendicular to the length direction of the conduction wire 15. Therefore, reference numeral 15w is the line width of the conduction line 15.

The transparent photoresist 16r is not used during ordinary photolithography etching, but a portion that has been exposed and cured is used as a component of a component later. In this sense, it can also be called a permanent resist. Therefore, it is desirable that the transparent photoresist 16r does not easily change over time in terms of transparency and haze value even after being cured to form the groove structure 16c.

Further, the transparent photoresist 16r needs to be less likely to cause color unevenness. This is because the transparent photoresist 16r covers most of the six-sided tempered glass 10. Therefore, it is necessary to have a retardation characteristic that does not give a sense of discomfort to the naked eye even when used together with the six-sided tempered glass 10. For example, ATN1021 negative acrylic resist manufactured by Dow Chemical Co., Ltd. can be suitably used as a transparent photoresist.

Further, since the transparent photoresist 16r receives ultraviolet rays not only from the sunlight but also from the display device 42 (see FIGS. 5 and 6) described later, it is liable to deteriorate. Therefore, the transparent photoresist 16r contains at least one of an ultraviolet absorber and a radical scavenger. As a result, the transparent photoresist 16r is less susceptible to changes over time due to ultraviolet rays.

The second electrode layer 22 has the same structure as the first electrode layer 16, and the conduction wire 15 is formed by filling the groove structure 22c formed on the transparent photoresist 22r with the electrode layer 22m. In the second electrode layer 22, the directions of the first electrode layer 16 and the sensing line 22a are different (see FIG. 1). Further, the Y-direction address line 22b is also provided in a direction different from that of the first electrode layer 16. The second electrode 22 assumes a cross section cut along a plane parallel to the conductive wire 15.

The intermediate layer 18 is a layer arranged between the first electrode layer 16 and the second electrode layer 22. It is a transparent resin with a thickness of about 5 μm. The so-called optical glue can be suitably used for the intermediate layer 18.

Next, a method for manufacturing the transparent touch pad 10 according to the present invention will be described. 3 and 4 show a process diagram of the manufacturing process of the transparent touch pad 10 shown in FIG. See FIG. 3 (a). A six-sided tempered glass 12 that has been formed into a size to be used in advance and then undergoes a strengthening process is prepared as a substrate.

Next, the plating catalyst layer 14 is formed on one surface of the six-sided tempered glass 12. The plating catalyst layer 14 is used as a coating material by dispersing a metal substance containing Pd, Ni, Pt, Cu and the like or a polymer member impregnated with these and a solvent. Then, the paint is applied to the six-sided tempered glass 12. When the solvent volatilizes and dries, a plating catalyst layer 14 having a diameter of about 30 nm can be formed.

See FIG. 3 (b). A transparent photoresist 16r is applied onto the plating catalyst layer 14. The thickness is preferably about 2 to 3 μm. Next, a groove structure 16c is formed on the transparent photoresist 16r (FIG. 3 (c)). The transparent photoresist 16r in which the groove structure 16c is formed may be referred to as a grooved transparent resist. The groove structure 16c is formed so that the plating catalyst layer 14 which is the lower layer is exposed. This is because electroless plating cannot be performed unless the plating catalyst layer 14 is exposed.

The groove structure 16c can be performed by dry etching. However, at this time, it is necessary to pay attention to the temperature rise of the six-sided tempered glass 12. The six-sided tempered glass 12 is subjected to heat treatment to reduce strain and reduce its strength. Therefore, it is necessary to perform dry etching in a short time so that the temperature of the six-sided tempered glass 12 does not rise.

After applying the transparent photoresist 16r, a groove structure 16c is formed by microstamping before the transparent photoresist 16r is completely cured, and only the transparent photoresist 16 that remains thin at the bottom of the groove is dry-etched. When removed, the groove concept 16c can be formed without raising the temperature of the six-sided tempered glass. At this time, the address line 16a in the X direction may also be formed at the same time.

See FIG. 3 (d). The six-sided tempered glass 12 in which the groove structure 16c is completed is electroless plated to form a metal layer 16m. The metal layer 16m is filled in the groove structure 16c by electroless plating a conductive metal. As the metal type, a good conductive substance such as copper, silver or gold is preferably used. Among them, copper, which has excellent conductivity and low cost, is one of the most preferably available metal species. The first electrode layer 16 is formed as described above.

See FIG. 3 (e). Next, the intermediate layer 18 is formed on the first electrode layer 16. As already described, the intermediate layer 18 is preferably about 5 μm. For example, a material called optical glue is applied to a dry thickness of 5 μm, and the whole is dried well. The intermediate layer 18 serves as a substrate for the second electrode layer 22.

See FIG. 4 (f). FIG. 4 is a continuation of the process from FIG. The plating catalyst layer 20 is formed on the intermediate layer 18. The forming method is the same as in the case of FIG. 3A.

See FIG. 4 (g). A transparent photoresist 22r is applied onto the well-dried intermediate layer 18. The coating method is the same as in the case of FIG. 3 (b). Then, the groove structure 22c is formed by microstamping before the transparent photoresist 22r is completely cured. The transparent photoresist 22r on which the groove structure 22c is formed may be referred to as a grooved transparent resist. Then, the transparent photoresist 22r is removed by dry etching so that the plating catalyst layer 20 is exposed (FIG. 4 (h)). Note that FIG. 4H shows a cross section of a portion of the conduction wire 15 along the longitudinal direction.

With reference to FIG. 4 (i), the metal layer 22 m is formed by electroless plating using the exposed plating catalyst layer 20. Through the above steps, the transparent touch pad 10 according to the present invention can be obtained. Since the groove structure 22c of the second electrode layer 22 is filled with the metal layer 22m, the surface of the second electrode layer 22 can be formed to be smooth. Therefore, there is no uneven adhesion when the transparent touch pad 10 is connected to other devices.

In the steps of removing the transparent photoresists 16r and 22r to expose the plating catalyst layers 14 and 20 (FIGS. 3 (c) and 4 (h)), the transparent photoresists 16r and 22r are micro-stamped with conductive wires 15. The method of imprinting the pattern of the above and then performing dry etching has been exemplified, but the method is not limited to this method.

The transparent touch pad 10 according to the present invention is characterized in that the six-sided tempered glass is not heat-treated to reach 100 ° C. or higher. It is said that the six-sided tempered glass 12 loses its strength due to its strain being relaxed when it is heat-treated at about 120 ° C. or higher, but the strength can be maintained if it is treated at a temperature of 120 ° C. or lower. Therefore, the transparent photoresists 16r and 22r may be removed by a method other than the methods described in FIGS. 3 (c) and 4 (h) as long as the strength is not lost. For example, methods such as wet etching and intermittent dry etching can be mentioned.

5 and 6 show the configuration of the touch panel 40 using the transparent touch pad 10 obtained as described above. FIG. 5 is a perspective view, and FIG. 6 is a partial cross-sectional view. The touch panel 40 is formed by adhering the electrode portion 13 of the transparent touch pad 10 and the display device 42 with the optical glue 44 with reference to FIGS. 5 and 6. In FIG. 4, the X address line 16b and the Y address line 16b are omitted.

The optical glue layer 44 is a layer made of an optical adhesive called OCA (Optical Clear Adhesive). Known materials can be used for this. For example, there are those containing an acrylate compound as a main component, those using a thiol compound, and those using a resin having a fluorene ring.

FIG. 7 shows the configuration of the communication terminal 50 using the touch panel 40 and the electronic device 60. A communication terminal 50 is configured by connecting a control unit 52, a communication unit 54, a camera 56c, a speaker 56s, and a battery (not shown) to the touch panel 40 shown in FIG. The transparent touch pad 10 transmits the change in the capacitance on the surface of the six-sided tempered glass 12 to the control unit 52 as a signal Sc through the X-direction address line 16a and the Y-direction address line 16b. By receiving the signal Sc, the control unit 52 detects which position of the six-sided tempered glass 12 is touched, and controls based on the position.

Further, the control unit 52 transmits the signal Si to the display device 42. The display device 42 displays according to the signal Si.

Further, the control unit 52 may perform image processing on the signal from the camera 56c. Further, the control unit 52 may output the instructed data from the speaker 56s. The speaker 56 includes an earphone and a headphone terminal. Further, the control unit 52 may send and receive signals to and from the outside through the communication unit 54. The communication unit 54 includes a connection with a solid-state memory.

Further, the control unit 52 does not have to be integrated into one chip, and may be divided into a plurality of control chips for each function.

Further, the electronic device 60 may have a form in which the operating unit 62 is connected to the control device 52 of FIG. 7. The operating unit 62 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 10 according to the present invention can be mounted on the electronic device 60 and used.

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.

10 Touch panel 12 Six-sided tempered glass 12
14 Plating catalyst layer 15 Conduction line 16 First electrode layer 16a X-direction sensing line 16b X-direction address line 16c Groove structure 16r Transparent photoresist 16m Metal layer 18 Intermediate layer 20 Plating catalyst layer 22 First electrode layer 22a X-direction sensing line 22b X-direction address line 22c Groove structure 22r Transparent photoresist 22m Metal layer 40 Touch panel 42 Display device 44 Optical glue 50 Communication terminal 52 Control unit 54 Communication unit 56c Camera 56s Speaker 60 Electronic device 62 Operating unit

Claims (1)

Six-sided tempered glass and
On one side of the six-sided tempered glass,
A groove structure formed of a transparent photoresist via a plating catalyst layer,
It has an electrode layer composed of a metal layer arranged in the groove structure, and has an electrode layer.
A transparent touch pad characterized in that the transparent photoresist contains at least one of an ultraviolet absorber and a radical scavenger.

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