JP2013214185A - Touch panel sensor and manufacturing method of the same - Google Patents

Abstract

An object of the present invention is to provide a capacitive touch panel sensor with low wiring resistance, stable operation, high transmittance, and low cost.
A glass substrate 1 having a thickness of 0.10 ± 0.01 mm is provided with mesh-like copper wirings 7 and 8 on each of the front and back portions of the glass substrate 1 that need to be seen. A touch panel sensor 10 having a copper wiring for drawing a copper wire, wherein the copper wirings are insulated from each other and the mesh copper wirings on the front and back sides are arranged at a half pitch. is there.
[Selection] Figure 3

Description

  The present invention relates to a capacitive touch panel sensor used as coordinate input means, and more particularly to an electrode arrangement of a touch panel sensor in which an electrode support is an extremely thin glass substrate.

  2. Description of the Related Art In recent years, touch panel type input devices (hereinafter simply referred to as touch panels) have been adopted for operation units of various electronic devices such as mobile phones, portable information terminals, and car navigation systems. The touch panel 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 panels, 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 the capacitance does not depend on the impedance of the contact medium.

  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 is too high in the case of ITO wiring. 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. Further, when 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 was a problem that the process and equipment were required and the cost was increased.

  On the other hand, touch panels with light-shielding metals arranged in a matrix form have a low sensitivity, a low aperture ratio, and darkness because the number of metal lines per unit area is small and the line width is large, regardless of whether the substrate is a film or a glass substrate. was there. In particular, a glass substrate can be manufactured by a roll method in terms of construction method, but has a problem of low transmittance.

  In view of the above problems, the present invention has an object to provide an inexpensive capacitive touch panel sensor that operates stably with low wiring resistance and high transmittance.

  In order to achieve the above-mentioned object, the invention according to claim 1 is to provide a mesh-like copper wiring in a portion requiring a see-through of a glass substrate having a thickness of 0.10 ± 0.01 mm, and the mesh in a portion not requiring the see-through. A touch panel sensor including a copper wiring for drawing out a copper wire, wherein the copper wiring is insulated from each other.

  The invention according to claim 2 is provided with a striped copper wiring on each of the front and back surfaces of the glass substrate having a thickness of 0.10 ± 0.01 mm that needs to be seen through, and the stripe-like shape on each of the portions that do not need to be seen through. A touch panel sensor provided with copper wiring for drawing out copper wiring, wherein the copper wiring is insulated from each other, and the striped copper wiring is arranged so as to be orthogonal on the front and back. Is.

  According to a third aspect of the present invention, a mesh-like copper wiring is provided on each part of the front and back surfaces of the glass substrate having a plate thickness of 0.10 ± 0.01 mm that requires perspective, and the mesh is disposed on each part that does not require perspective. A touch panel sensor provided with a copper wiring for drawing out copper-like copper wiring, wherein the copper wiring is insulated from each other, and the mesh copper wiring on the front and back sides is arranged with a half-pitch shift. Is.

  The invention according to claim 4 is characterized in that, for the glass portion that needs to be seen through, the pitch of the copper wiring is in the range of 100 to 500 μm and the line width is 10 μm or less. The touch panel sensor according to any one of the items is used.

  The invention according to claim 5 is characterized in that an aperture ratio of the glass portion that needs to be seen through is in a range of 90 to 98%, and a line width of the lead wire is in a range of 0.02 to 0.50 mm. The touch panel sensor according to claim 1 or claim 2 is provided.

  The invention according to claim 6 is characterized in that, for the glass portion that needs to be seen through, the copper wiring has a surface resistance of 3Ω / □ or less and a capacitance of 0.5 to 3.0 pF. The touch panel sensor according to any one of claims 1 to 4.

According to a seventh aspect of the present invention, at least a resist layer is formed by a step of forming a resist layer on a copper thin film supported on a roll-shaped glass substrate having a plate thickness of 0.10 ± 0.01 mm, and a photolithography method. Process into striped wiring pattern and lead wiring pattern, stripping exposed copper thin film by etching to form striped copper wiring and lead copper wiring, and softening resist on striped copper wiring And letting it sag,
And a step of forming a striped copper wiring so as to cross over the sag resist portion and to be orthogonal to the striped copper wiring.

  The invention according to claim 8 is a method for manufacturing a touch panel sensor, characterized in that the method for manufacturing a touch panel sensor according to claim 7 is applied to front and back copper thin films supported by a roll-shaped glass substrate. It is.

  The invention according to claim 9 is the method of manufacturing a touch panel sensor according to claim 7 or 8, wherein the copper thin film is a deposited copper foil and has a thickness of 2.0 μm or less. It is.

  According to the first aspect of the present invention, since a light and thin glass substrate is used, a light and thin touch panel sensor with high transmittance can be provided. Moreover, since it can manufacture by a roll-to-roll system, it can manufacture at low cost.

According to the invention described in claim 2, since a light and thin glass substrate is used, a light and thin touch panel sensor with high transmittance can be provided. Moreover, since it can manufacture by a roll-to-roll system, it can manufacture at low cost.
Furthermore, in the present invention, since the striped electrodes are laid so as to be orthogonal to the front and back of the glass substrate, there is an effect that it is not necessary to newly form an insulating layer in order to insulate the upper and lower electrodes.

  According to the invention described in claim 3, since the same independent touch panel sensor is provided on each of the front and back surfaces of the glass substrate, and they are laid out with a half-pitch offset from each other, the effect of claim 1 is added. When viewed from the front, compared to the case where a single sensor is provided on the surface, this corresponds to the fact that the sensor is arranged at a high density (twice), and there is an effect that the sensor sensitivity and the resolution as a position sensor are improved. If the sensor density is the same, the sensor processing scale can be increased to facilitate processing, improve manufacturing yields, and reduce costs.

  In addition, the number of substrates is smaller and lighter than a stacked touch panel in which two touch panel sensors each having a mesh arrangement on one side are bonded together, so that members, processing costs, and the like can be saved. There is little wasteful optical reflection (from the adhesive layer or the like) due to multilayering.

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

  According to the invention which concerns on Claim 5, if the line width of a copper wiring is made into the value of Claim 4, and an aperture ratio shall be 90% or more, a bright image display can be anticipated when integrated with a display.

  According to the invention of claim 6, if the surface resistance is set to about 3Ω / □ or less and the capacitance is set in the range of 0.5 to 3.0 pF, a highly sensitive and stable operation can be expected as a touch panel.

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

Further, in the case where the upper stripe stripe wiring is laid perpendicularly to the lower stripe wiring and the mesh portion needs to be insulated by interposing an insulating resin at the intersection.
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 on the glass surface. I am doing so. As a result, it is possible to prevent the upper copper wiring from contacting the lower copper wiring and to prevent 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. However, since a glass substrate is used, it has heat resistance, so that the temperature can be raised above the melting point of the resist regardless of negative / positive. Since the resist easily fluidizes, the side surface of the copper electrode can be easily coated.

  In the invention according to claim 8, a touch panel having a touch panel on the front and back of the glass substrate is obtained.

  According to the ninth aspect of the present invention, when the resist is softened and sagged 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 panel which provided the mesh structure in the glass substrate single side | surface. It is the figure of the upper surface view and cross-sectional view of the touch panel which provided the striped electrode on each of both surfaces of a glass substrate, 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 sectional view of the touch panel which provided the mesh structure on each of both surfaces of the glass substrate. Solid line indicates front side, double line indicates back side It is a figure 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. (A)-(f) It is process drawing which illustrates typically the manufacture process of the cross | intersection part of the mesh electrode of a touchscreen sensor.

  Hereinafter, embodiments of a touch panel sensor (hereinafter simply referred to as a touch panel) using an ultrathin glass substrate according to the present invention will be described with reference to the drawings.

  The touch panel sensor is grounded when an electrostatic and conductive medium such as a finger or hand is brought close to the conductor when alternating current with the same phase and the same voltage is applied to both ends of the conductor. 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. Of course, all the electrodes in the X direction and 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 higher 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 arrangement for the sake of convenience, but is a linear electrode arrangement form that forms a square lattice in a top view.
However, if the resolution can be changed, it is not always necessary to use a square lattice, and the pitch may be different.

  Now, the first embodiment is shown in FIG. 1, and the aperture ratio falls within the range of 90 to 98% on one side of the region where the glass substrate having a thickness of 0.10 ± 0.01 mm needs to be seen through. Thus, the touch panel 10 is provided with copper wiring in a mesh shape. That is, striped copper wirings having the same pitch are arranged on one side of the glass substrate 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 panel 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 is at least approximately the same size as these image display units. However, if the entire range is not the input range of the touch panel, the mesh electrode 10 may not be provided even if it is a fluoroscopic range. Generally, it is painted black in a frame shape (decoration) so that it is not visible outside the range that requires perspective.

  The individual copper wirings 2 and 3 constituting the mesh electrode 10 are all led to the outer periphery of the glass substrate and connected to the external connection terminal 6 '(the same applies to the embodiments 2 and 3). 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 glass substrate 1. All copper wiring needs to be insulated from each other as long as they are used as sensors.

  Assuming that the width of the mesh opening 9 partitioned by the copper wiring is a and the wiring width of the light shielding portion is d, d / a = 0.05 at an opening ratio of 90% and d / a = 0.01 at an opening ratio of 98%. Degree. 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 preferably performed with an insulating resin layer 5 having a thickness of 1 to 2 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 (different from the figure). 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, stripe-shaped copper wirings 2 and 3 having the same pitch are provided on both sides of the glass substrate 1, that is, the front and back surfaces, and are orthogonal to each other. It is arranged. The solid line corresponds to the front surface, and the double line corresponds to the back surface. Since the glass substrate 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 includes the mesh structure 7 and the mesh structure 8 of the first embodiment on the front and back of the glass substrate 1, and the front and back meshes 7 and 8 are only a half pitch in top view. It is arranged so as to be displaced. This is the same as the first embodiment in which the pitch is halved, but there is an advantage that wiring processing becomes easier due to the wider pitch.
In addition, there is an advantage that the glass substrate having the mesh electrode on one side is thinner and lighter than a glass substrate bonded 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 Embodiments 2 and 3, since the glass substrate 1 having a thickness of about 100 μm is interposed between the upper and lower wirings, it is preferable to set the capacitance in the range of 0.5 to 3 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 using FIG.

  A roll-shaped glass substrate having a thickness of 0.10 ± 0.01 mm can be obtained from, for example, Nippon Electric Glass. It manufactures by a roll-to-roll system using this roll-shaped glass substrate.

  As the copper thin film, an electrolytic copper foil or a rolled copper foil having a smooth surface of 10 to 30 μm is laminated on the roll-shaped glass substrate via an adhesive, or a thickness of 2 μm is formed on the glass substrate by vapor deposition. What formed the copper layer of the grade 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 a glass substrate.

  First, a roll-shaped glass substrate laminated with a copper foil is prepared (FIG. 5A). For patterning of the copper foil 15, in principle, a regular photolithography method is used.

Next, a resist 16 is applied on the copper foil 15 to a thickness of about 2 μm (FIG. 5B), and is brought into proximity using a photomask having a stripe pattern constituting the mesh portion and an extraction electrode pattern and the like. After exposure, development is performed to form a resist pattern (FIG. 5C). A copper wiring pattern 17 is formed by etching away the copper foil exposed to the opening with a ferric chloride solution of about 60 degrees (FIG. 5D).

  In Embodiment 2, since the wiring patterns 17 do not overlap, the above processing may be performed separately on the front and back of the glass substrate 1 or simultaneously.

  In the first and second embodiments, copper wiring patterns 18 having the same pitch are formed in a direction orthogonal to the copper wiring pattern 17 of the first stripe. In the intersection 13, it is necessary to form an insulating layer so that the lower copper wiring 17 and the upper copper wiring 18 do not short-circuit. An insulating resist pattern may be formed again after the resist 16 ′ remaining on the wiring is peeled off using the first copper wiring pattern 17 for photolithography, or the remaining resist 16 ′ may be used. You can also. The latter is preferable because it requires less man-hours.

  For the latter, the correspondence between the negative resist and the positive resist is slightly different, but the goal is to change the resist 16 'remaining on the copper wiring 17 so as to cover the side surface of the etched copper wiring and draw a skirt. (FIG. 5E). This is because, if not in such a form, there is a risk of shorting or breaking with the subsequent copper wiring 18. For this reason, it is desirable that the thickness of the copper wiring 17 is thin, and it is preferably about 2.0 μm or less.

  With respect to the positive resist, when the glass substrate 1 is heated to a temperature equal to or higher than the melting point of the resist, the positive resist is fluidized and sagged to obtain the desired form 19, and at the same time, the 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 resist shape of the intersecting portion 13 is made into a skirt shape, a copper wiring pattern 18 in an orthogonal direction is formed by a photolithography method (FIG. 5F). The second copper foil forming method is not particularly defined, but the vapor deposition method is preferable. Etching can be performed simultaneously at the front and back, which is a desirable processing method.

DESCRIPTION OF SYMBOLS 1, Glass substrate 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 glass substrate surface, Mesh structure 9 on the back surface of the glass substrate, Mesh opening 10. Mesh structure (touch panel)
11. X direction electrode (ITO)
12, Y direction electrode (ITO)
13, intersection 14, lead electrode 15, copper foil 16, resist layer 16 ′, remaining resist layer 17, copper wiring pattern (lower part)
18. Copper wiring pattern (top)
19. Depressed resist layer

Claims (9)

  A touch panel sensor comprising a glass substrate having a thickness of 0.10 ± 0.01 mm and a mesh-like copper wiring in a portion that requires see-through, and a copper wire for drawing out the mesh-like copper wire in a portion that does not require see-through. The touch panel sensor is characterized in that the copper wirings are insulated from each other.   Striped copper wiring is provided on each of the front and back surfaces of the glass substrate having a thickness of 0.10 ± 0.01 mm that need to be seen through, and the copper wiring for drawing out the striped copper wiring is provided on each of the portions that do not need to be seen through. It is a touch panel sensor provided, wherein the copper wirings are insulated from each other, and the striped copper wirings are arranged so as to be orthogonal to each other on the front and back sides.   Each part of the glass substrate with a thickness of 0.10 ± 0.01 mm, which needs to be seen through, is provided with a mesh-like copper wiring, and each of the parts that do not need to be seen through has a copper wiring for drawing out the mesh-like copper wiring. A touch panel sensor comprising: the copper wirings are insulated from each other, and the mesh copper wirings on the front and back sides are arranged with a half-pitch shift.   The touch panel according to any one of claims 1 to 3, wherein the glass 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. sensor.   The aperture ratio of the glass portion that needs to be seen through is in the range of 90 to 98%, and the line width of the lead line is in the range of 0.02 to 0.50 mm. The touch panel sensor according to item 1.   The glass portion that needs to be seen through has a copper wiring having a surface resistance of 3Ω / □ or less and a capacitance of 0.5 to 3.0 pF. The touch panel sensor according to any one of claims. At least a step of forming a resist layer on a copper thin film supported by a roll-shaped glass substrate having a plate thickness of 0.10 ± 0.01 mm;
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 the sagged resist portion and to be orthogonal to the striped copper wiring.   The manufacturing method of the touch panel sensor of Claim 7 is applied to the copper thin film of the front and back supported by the roll-shaped glass substrate.   The method for manufacturing a touch panel sensor according to claim 7 or 8, wherein the copper thin film is a vapor-deposited copper foil and has a thickness of 2.0 µm or less.