JP2013186632A - Film-like touch panel sensor and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bright and low cost capacitance type touch panel sensor with low wiring resistance which is capable of operating stably.SOLUTION: A film-like touch panel sensor includes a film 1 having: mesh-like copper wires 7, 8 on areas requiring transparency in a front face and a back face, respectively: and copper wires for drawing the mesh-like copper wires on areas requiring no transparency. The copper wires are insulated with each other. The mesh-like copper wires 7, 8 in front and back faces are arranged at a half pitch deviation, an opening ratio of the area is within a range of 90-98%, and a linewidth of the copper wires for drawing is within a range of 0.02-0.50 mm.

Description

  The present invention relates to a capacitive touch panel used as coordinate input means, and more particularly to an electrode arrangement of a touch panel sensor using an electrode support as a film.

  2. Description of the Related Art In recent years, touch panel type input devices (hereinafter referred to as touch panel sensors or simply referred to as sensors) have been adopted in operation units of various electronic devices such as mobile phones, personal digital assistants, and car navigation systems. The touch panel sensor is used as an input device that detects a contact position of a fingertip or a pen tip on a display surface of a display panel such as a liquid crystal display device or an organic EL device. There are various types of touch panel sensors such as a resistance film type and a capacitance type depending on the structure and detection method.

  There are two types of capacitive touch panel sensors: surface type and projection type. Both methods detect the position by capturing the change in capacitance between the fingertip and the conductive film. Since electrostatic coupling occurs only when the finger approaches the sensor surface, it is possible to display a cursor before contact. The object to be pressed needs to be a finger or an electrostatically conductive material equivalent to that of the finger, but the alternating current that flows in accordance with the change in capacitance does not depend on the impedance of the medium to be contacted.

  In particular, the projected capacitive method can detect multiple points of the fingertip. In general, the projection type has a configuration in which a support substrate on which an electrode layer and a control IC are mounted is covered with a protective insulating resin. An example of the electrode layer is shown in FIG. 4, but a large number of mosaics comprising a set of X and Y electrodes 11 and 12 using a transparent electrode material (ITO) on a support substrate such as glass or plastic. It consists of an electrode. The X direction electrode 11 and the Y direction electrode 12 are all laid while maintaining insulation (Patent Documents 1 and 2).

  As shown in FIG. 1, stripe-shaped metal wires 2 extending in the vertical direction (inclined by 45 ° in the figure) and metal wires 3 extending in the horizontal direction may be laid on the substrate 1 while maintaining insulation. No (Patent Documents 3 and 4). Since metal is light-shielding and reflective, unlike ITO, wiring density and aperture ratio are problematic. Regardless of whether the ITO array or the metal array is touched or approached, the position can be accurately identified by knowing the change in the capacitance of the nearby electrode from one set of vertical and horizontal electrode arrays.

  Although many points can be detected by a large number of electrode rows running vertically and horizontally, the number of terminals is large and the resistance of the ITO wiring becomes too high, so that it is not suitable for a large screen as it is. Therefore, in a large touch panel, in order to connect an FPC on which an IC for position detection is mounted and a sensor board, a wiring for taking out with a large line width is provided around the board. Tend to be higher. However, it has the highest practicality because it can detect multiple points, and is widely used in tablet-type portable terminals.

JP 2011-86122 A JP 2008-210850 A Japanese Patent No. 4610416 JP 9-51186 A

  However, since the ITO transparent electrode used for the electrode of the capacitive touch panel sensor has low conductivity, the sensitivity is deteriorated in the case where the finger does not directly touch the ITO. Therefore, there was a problem that the input could not be read reliably and malfunctioned. In addition, an extra step is required if a metal electrode such as aluminum is attached to ITO, or a portion with a narrow line width such as a constriction portion 13 shown in FIG. 4 is replaced with metal (MAM; molybdenum / aluminum / molybdenum). There is a problem that the equipment is required and the cost is increased.

On the other hand, a touch panel in which light-shielding metals are arranged in a matrix has a problem that the number of metal lines per unit area is small and the line width is large, so that the sensitivity is low and the aperture ratio is low and dark.
In view of the above-described problems, the present invention has an object to provide a capacitive touch panel sensor that has a low wiring resistance, operates stably, and is bright and inexpensive.

  The invention according to claim 1 of the present invention is a touch panel sensor including a mesh-like copper wiring on a portion of the film surface that needs to be seen through and a copper wiring for drawing out the mesh-like copper wiring on a portion that does not need to be seen through. The copper wirings are insulated from each other, the opening ratio of the mesh portion is in the range of 90 to 98%, and the line width of the drawing copper wiring is in the range of 0.02 to 0.50 mm. It is a touch panel sensor.

  The invention according to claim 2 of the present invention is provided with a striped copper wiring in each of the portions requiring the perspective of the film surface and the back surface, and a copper wiring for drawing out the striped copper wiring in the portion not requiring the perspective. In the touch panel sensor, the copper wirings are insulated from each other, the striped copper wirings on the front and back sides are arranged orthogonally, the aperture ratio of the part is in the range of 90 to 98%, and the line width of the lead-out wiring is 0 A film-shaped touch panel sensor characterized by being in a range of 0.02 to 0.50 mm.

  The invention according to claim 3 of the present invention is provided with a mesh-like copper wiring in each of the portions requiring the perspective of the film surface and the back surface, and a copper wiring for drawing out the mesh-like copper wiring in a portion where the perspective is unnecessary. In the touch panel sensor, the copper wirings are insulated from each other, the mesh copper wirings on the front and back sides are arranged with a half pitch shift, the aperture ratio of the portion is in the range of 90 to 98%, and the line width of the lead-out wiring is 0 A film-shaped touch panel sensor characterized by being in a range of 0.02 to 0.50 mm.

  The invention according to claim 4 of the present invention is characterized in that the film portion that needs to be seen through has a copper wiring pitch in the range of 100 to 500 μm and a line width of 10 μm or less. The film-shaped touch panel sensor according to any one of Items 3 is obtained.

  The invention according to claim 5 of the present invention is that, for the film portion that needs to be seen through, the copper wiring has a surface resistance of 1Ω / □ or less and a capacitance of 0.1 to 10.0 pF. The film-like touch panel sensor according to any one of claims 1 to 4, wherein the film-like touch panel sensor is provided.

  In the invention according to claim 6 of the present invention, at least the resist layer is processed into a striped wiring pattern and a drawing wiring pattern by a photolithographic method by forming a resist layer on the copper thin film supported by the film. Removing the exposed copper thin film by etching, forming a striped copper wiring and a lead copper wiring, softening the resist on the striped copper wiring and sagging, and sagging the resist portion And a step of forming a striped copper wiring so as to be orthogonal to the striped copper wiring.

  The invention according to claim 7 of the present invention applies the method for manufacturing a film-like touch sensor according to claim 6 to the copper thin films on the front and back sides supported by the film. It is what.

  The invention according to claim 8 of the present invention is the film-shaped touch sensor according to claim 6 or 7, wherein the copper thin film is a deposited copper foil and has a thickness of 2.0 μm or less. It is a manufacturing method.

According to the first aspect of the present invention, the mesh portion and the lead-out wiring for external connection are configured by copper wiring on one side of the film, so that the aperture ratio is smaller than the surface resistance value of 250 Ω / □ of the conventional ITO electrode The surface resistance can be kept as low as about 3Ω / □ at about 93%, and stable operation as a touch sensor can be expected.
Moreover, since the touch sensor is made of an inexpensive film and copper, a thin and light touch panel sensor can be provided at a lower cost than a combination of a glass substrate and ITO.

  In the invention according to claim 2, the same effect as that of the invention according to claim 1 can be expected. Furthermore, since the mesh structure of the wiring is realized by laying the wiring on the front and back surfaces of the film, the film naturally becomes an insulating resin, compared to the case where the mesh structure is formed on one side as in claim 1, There is an effect that it is not necessary to take insulation at the intersection. Accordingly, the manufacturing cost can be suppressed.

The invention according to claim 3 can be expected to have the same effect as the invention according to claim 1. In addition, in the present invention, a single independent touch panel sensor is provided on the film surface and the back surface, and they are laid out with a half-pitch shift from each other, so that when viewed from the film surface, a single sensor is provided on the film surface. Compared to the above, this corresponds to the fact that the sensors are arranged at high density (twice), and there is an effect that the sensor sensitivity and the resolution as a position sensor are improved.
In addition, if the sensor density is the same, the sensor processing scale can be increased to facilitate processing, improve the manufacturing yield, and reduce the cost.

  According to the invention described in claim 4, by setting the line width of the metal line sufficiently narrower than the stripe pitch of the metal wiring, it is possible to maintain a high sensor density and aperture ratio in a portion that requires fluoroscopy, and the metal line. Can be made inconspicuous.

  According to the invention of claim 5, as a result of maintaining sufficient sensor sensitivity, stable sensor operation without malfunction can be expected.

  According to the sixth aspect of the present invention, since the wiring of the sensor portion and the wiring to be taken out are collectively formed by etching of copper, the cost is lower than the conventional method using both ITO wiring and metal wiring.

  The mesh portion is composed of the lower layer stripe wiring and the upper stripe wiring orthogonal to the lower layer, but it is necessary to insulate the intersection portion by interposing an insulating resin. In the present invention, the resist covering the copper wiring used to form the lower stripe copper wiring is directly transferred to the insulating resin layer without being peeled off. In other words, by softening and sagging the resist that remains on the lower copper wiring and through which the upper copper wiring passes, the side surface of the lower copper wiring is covered and the slope is formed over the film surface. I am doing so. This prevents the upper copper thin film from coming into contact with the lower copper wire and prevents disconnection due to a steep step.

  The resist used for the patterning of the lower layer may be either a positive type or a negative type, but a resist having a very high melting point is not preferable because of the heat resistance temperature of the film. In this respect, it can be said that a positive resist is desirable.

  According to the seventh aspect of the invention, when the resist is softened and sagging by setting the copper thin film thin, it is easy to form the covering and slope of the copper wire side portion at the intersection, and between the copper wirings. There is an effect that short circuit and disconnection can be prevented.

It is the figure of the upper surface view and sectional view of the touch sensor which provided the mesh structure on the film single side | surface. It is the figure of the upper surface view and sectional view of the touch sensor which provided the striped electrode on each of both surfaces of a film, and was made into the mesh structure. A solid line indicates the front surface and a double line indicates the back surface. It is the figure of the upper surface view and cross-sectional view of the touch sensor which provided the mesh structure on each of both surfaces of a film. The solid line indicates the mesh structure on the front surface, and the double line indicates the mesh structure on the back surface. It is a schematic diagram of the top view which shows a mode that the ITO transparent electrode was spread | laid in mosaic shape as an X, Y direction electrode.

  Hereinafter, embodiments of a film-like touch panel sensor (hereinafter simply referred to as a touch sensor) according to the present invention will be described with reference to the drawings.

  A touch sensor is that when an alternating current with the same phase and the same voltage is applied to both ends of a conductor and an electrostatic and conductive medium such as a finger or hand is brought close to the conductor, it is grounded. It is an electronic device that utilizes the phenomenon that capacitive coupling occurs between an assumed medium and a conductor (since this is also grounded) and an excessive alternating current flows through the conductor.

  Therefore, it is not necessary for the finger to touch the conductor directly, and the conductor may be contacted or approached via the dielectric. Since the conductor is soiled when the hand touches the conductor of the sensor unit, the conductor is usually used by being coated with an antifouling transparent resin, and the conductor (hereinafter referred to as an electrode). ) Do not necessarily exist on the same plane, and may be disposed between insulating resins or the like. However, since the substantial distance to the contact medium (for example, a finger) changes, there is a possibility that the sensitivity changes depending on whether the sensitivity is above or below the insulating resin.

  In principle, it is possible to detect which electrode material is close to which side by simply placing the electrode material appropriately, but in order to maintain accuracy as a position sensor, linear electrodes are arranged in an XY matrix. Thus, the position is calculated from the intersection by independently detecting only which X direction electrode and which Y direction electrode, not where on which electrode. Naturally, the electrode in the X direction and the electrode in the Y direction need to be insulated. Moreover, the electrode does not necessarily need to be linear.

  Therefore, if a transparent electrode material is used, as shown in FIG. 4, the X-direction electrode 11 and the Y-direction electrode 12 are arranged in a mosaic pattern because they do not hinder the see-through. This is because the wider the area, the better the sensitivity. The portion 13 where the X electrode and the Y electrode intersect has a structure that does not contact each other. In the case of a light-shielding metal, fine lines that are invisible as far as the transmittance allows are arranged as tightly as possible.

  In this specification, since the invention relates to the arrangement of the fine metal wires, the matrix arrangement is referred to as a mesh or a mesh structure for the sake of convenience, but is a linear electrode arrangement form that forms a square lattice in a top view.

  Now, the first embodiment is shown in FIG. 1, and the copper wiring in mesh form so that the aperture ratio is within the range of 90 to 98% on one side of the film, particularly the area where the PET film 1 needs to be seen. It is the touch sensor 10 provided with. That is, striped copper wiring having the same pitch is disposed on one side of the film 1 so as to be orthogonal to each other. The intersecting portion 4 needs to be insulated, and an insulating resin 5 is placed on one copper wiring 3 and the other copper wiring 2 crosses over the insulating resin 5.

  The range requiring fluoroscopy is that the touch sensor 10 is used in an overlapping manner on an image display unit of a display device such as an LCD or an organic EL, and therefore is at least approximately the same size as these image display units. However, when the entire range is not the input range of the touch sensor, there is no mesh electrode 10 even in the fluoroscopic range. It is painted black so that it is not visible except for areas that require fluoroscopy (decoration).

  The individual copper wires 2 and 3 constituting the mesh electrode 10 are all guided to the outer periphery of the film and connected to terminals for external connection. This wiring is called the lead-out wiring 6 and is preferably inexpensive and low-resistance copper. In a portion that is not seen through, the line width can be increased within an allowable range. In this case, a range of approximately 0.02 to 0.5 mm is preferable. Either one of the mesh-like copper wirings 2 and 3 and the drawing copper distribution wiring 6 are collectively formed from a copper thin film laminated on the same film 1.

  If the width of the mesh opening 9 partitioned by the copper wiring is a and the width of the light shielding part is d, the opening ratio is about 90%, d / a = 0.05, and the opening ratio is 98%, d / a = 0.01. It is. Since the line width d of the light-shielding metal is said to be invisible when it is approximately 20 μm or less, the side a of the opening is in the range of 400 to 2000 μm when the line width d = 20 μm. The narrower line width d = 10 μm needs to be in the range of 200 to 1000 μm, and d = 5 μm in the range of 100 to 500 μm.

  Insulation of the upper and lower copper wirings of the mesh intersection 4 is performed with an insulating resin layer 5 having a thickness of about 2 to 10 μm interposed therebetween. If the side surface of the insulating resin layer 5 is nearly vertical, there is a risk of disconnection depending on the method of forming the overlying copper wiring 2. Therefore, it is desirable that the shoulder of the insulating resin layer 5 changes smoothly. After the lower layer copper wiring 3 is formed by a regular photolithography method, the resist remaining on the copper wiring is peeled off, and then a fine resist pattern can be formed again at the intersection 4 by the photolithography method.

  Alternatively, as will be described later, the remaining resist can be diverted to the insulating layer 5. It is desirable that the resist used in the photolithography method is peeled off except for the intersection 5. It is not preferable to leave the openings 9 because the number of layers increases and multiple reflections and Newton rings are caused.

  The second embodiment is a mode shown in FIG. In the first embodiment, a mesh structure is formed on one side, but in this embodiment, striped copper wirings 2 and 3 having the same pitch are provided on both sides of the film, that is, on the front and back surfaces, and arranged so as to be orthogonal to each other on the front and back sides. It is. The solid line corresponds to the wiring on the front surface, and the double line corresponds to the wiring on the back surface. Since the film 1 is between the copper wiring 2 and the copper wiring 3, it is not necessary to separately provide the insulating layer 5 at the intersection 4 as in the first embodiment. The top view is exactly the same as in the first embodiment.

  As shown in FIG. 3, the third embodiment is provided with the mesh structure 7 and the mesh structure 8 of the first embodiment on the front and back of the film 1, and the meshes 7 and 8 on the front and back are shifted by a half pitch when viewed from above. It is arranged as follows. This is the same as the first embodiment in which the pitch is halved, but the wiring process has the advantage that the pitch is wider (particularly the terminal portion 9). In addition, the single-sided film of Embodiment 1 may be laminated back to back.

  In the first to third embodiments, the surface resistance of the copper wiring needs to be set to about 3Ω / □ or less. This is because the sensor sensitivity is higher when the resistance is lower. In Embodiment 2 and Embodiment 3, although the film 1 having a thickness of about 20 to 130 μm is interposed between the upper and lower wirings, the capacitance is preferably set in the range of 0.1 to 10 pF.

  Incidentally, the surface resistance was 0.3Ω / □ (by the four-terminal method) when the electrolytic copper foil was etched to form a mesh structure having a thickness of 13 μm, a line width of 10 μm, a pitch of 1000 μm, and an aperture ratio of 98%. The deposited copper foil had a thickness of 1.5 μm, a line width of 5 μm, a mesh pitch of 250 μm (substantially corresponding to the above-mentioned a), an aperture ratio of 93%, and a surface resistance of 3Ω / □. Although there are material differences in manufacturing method, the surface resistance can be controlled to a desired value within a range of 3Ω / □ or less.

  Next, the point which concerns on a manufacturing method is demonstrated.

  Regarding the film material, PET is preferable from the viewpoint of cost, but PEN or polyimide film can be used when heat resistance is required. In addition, polyethylene resin, polypropylene resin, methacrylic resin, cyclic polyolefin resin, polystyrene resin, acrylonitrile- (poly) styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), A film having a thickness in the range of 20 to 50 μm manufactured from polyvinyl chloride resin, poly (meth) acrylic resin, polycarbonate resin, polyester resin, polyamide resin, polyamideimide resin, or the like can also be used.

  As the copper thin film, a copper layer having a thickness of 10 to 30 μm and a smooth electrolytic copper foil or rolled copper foil laminated on the above film via an adhesive is used, or a copper layer having a thickness of about 2 μm is formed on the film by a vapor deposition method. Is used. Since the line width of the copper wire formed by etching the copper foil cannot be made thinner than the thickness of the copper foil, it is necessary to determine the type of the copper foil from the desired line width. When the line width is as thin as about 10 μm or less, it is preferable to use a copper thin film deposited on the film.

For the patterning of the copper foil, a conventional photolithography method is used.
First, a resist is applied on a copper foil with a thickness of about 2 μm, and proximity exposure is performed using a photomask provided with a stripe pattern constituting the mesh portion, an extraction electrode pattern, and the like. Development is performed to form a resist pattern, and the copper foil exposed to the opening is etched away with a ferric chloride solution of about 60 degrees to form a copper wiring pattern.

  In Embodiment 2, since the wiring patterns do not overlap, the above processing may be performed separately on the front and back of the film or simultaneously.

  In Embodiments 1 and 2, copper wiring patterns having the same pitch are formed in a direction perpendicular to the copper wiring pattern of the first stripe. At the intersection, it is necessary to form an insulating layer so that the upper and lower copper wirings do not short-circuit. After the resist remaining on the wiring is peeled off using the first copper wiring pattern photolithography, an insulating resist pattern may be formed again, or the remaining resist may be used.

  Regarding the latter, the correspondence between the negative resist and the positive resist is slightly different, but the goal is to transform the remaining resist so that it covers the side surface of the etched copper wiring and has a skirt. This is because if it is not in such a form, there is a risk of shorting or disconnection with the subsequent copper wiring.

For positive resists, if the resist is heated to a melting point or higher, it is fluidized and sagged to obtain a desired form, and at the same time, photoreactivity disappears. Prior to heating, re-exposure and development may be performed to remove the resist other than the intersection, and then heat treatment may be performed. Unnecessary resist does not remain on the wiring.

  Since the negative resist may be cured to have a high melting point, it is conceivable to form the first (lower layer) wiring in an insufficiently cured state. Alternatively, it is preferable that the resist surface on the copper foil is preferentially cured by adding an ultraviolet absorber or the like and developed so that side etching enters the base portion. Although it becomes a mushroom-like resist pattern, the side surface can be covered without raising the temperature so much because the resist is like a ridge after etching the copper foil.

  After the crossing portion is in such a form, a copper wiring pattern in the orthogonal direction is formed by a photolithography method. The second (upper layer) copper foil forming method is not particularly defined, but the vapor deposition method is preferred. Etching can be performed simultaneously at the front and back, which is a desirable processing method.

DESCRIPTION OF SYMBOLS 1, Film base material 2, X direction electrode 3, Y direction electrode 4, Crossing part 5, Insulating resin layer 6, Lead-out electrode 7, Mesh structure 8 on the film surface, Mesh structure 9 on the film back surface, Mesh opening part 10, Mesh Structure (touch sensor)
11. X direction electrode (ITO)
12, Y direction electrode (ITO)
13, intersection 14, lead electrode

Claims (8)

  A touch panel sensor having a mesh-like copper wiring on a part of the film surface that needs to be seen through and a copper wiring for drawing out the mesh-like copper wiring on a part that does not need to be seen through, wherein the copper wiring is insulated from each other and meshed. A film-like touch panel sensor, wherein the opening ratio of the portion is in the range of 90 to 98%, and the line width of the drawing copper wiring is in the range of 0.02 to 0.50 mm.   Each of the portions that need to be seen through on the front and back sides of the film is a touch panel sensor that includes a striped copper wiring, and a portion that does not need to be seen through has a copper wiring for drawing out the striped copper wiring. The striped copper wirings that are insulated from each other are arranged so as to be orthogonal to each other, the aperture ratio of the portion is in the range of 90 to 98%, and the line width of the lead-out wiring is in the range of 0.02 to 0.50 mm. A film-like touch panel sensor.   It is a touch panel sensor provided with a mesh-like copper wiring in each of the parts that need to be seen through on the front and back surfaces of the film, and a copper wiring for drawing out the mesh-like copper wiring in a part that does not require see-through, The mesh-like copper wirings that are insulated from each other are arranged with a half-pitch shift, the opening ratio of the portion is in the range of 90 to 98%, and the line width of the lead-out wiring is in the range of 0.02 to 0.50 mm. A film-like touch panel sensor.   The film according to any one of claims 1 to 3, wherein the film portion that needs to be seen through has a copper wiring pitch in a range of 100 to 500 µm and a line width of 10 µm or less. Touch panel sensor.   The film portion that needs to be seen through has a copper wiring having a surface resistance of 3Ω / □ or less and a capacitance of 0.1 to 10.0 pF. The film-like touch panel sensor according to any one of the above. At least a step of forming a resist layer on the copper thin film supported by the film;
A step of processing at least a resist layer into a striped wiring pattern and a drawing wiring pattern by a photolithography method;
Removing the exposed copper thin film by etching to form striped copper wiring and lead copper wiring;
A step of softening and sagging the resist on the striped copper wiring;
And a step of forming a striped copper wiring so as to cross over the sagging resist portion and to be orthogonal to the striped copper wiring.   The manufacturing method of the film-like touch sensor of Claim 6 is applied to the copper thin film of the front and back supported by the film, The manufacturing method of the film-like touch sensor characterized by the above-mentioned.   The said copper thin film is vapor deposition copper foil, and thickness is 2.0 micrometers or less, The manufacturing method of the film-form touch sensor of Claim 6 or Claim 7 characterized by the above-mentioned.