JP2015056025A - Cover material for touch panel, and touch panel using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cover material for a touch panel, configured to detect a contact position even when contact area of a stylus pen is smaller than that of a conventional one, and a touch panel using the cover material.SOLUTION: Cover materials 4, 5 for a touch panel are arranged between a capacitive touch panel with a sensor electrode and a conductive stylus pen 31. On a surface of a substrate 4 of the cover material, a resistive layer 5 is formed. The resistive layer 5 includes at least a transparent conductive thin film layer 6 having a predetermined surface resistivity set within a range of 10-10Ω/sq. When the stylus pen 31 comes into contact with the cover material, capacitance is changed between 0.45-5.29 pF/mmp per unit area, between a predetermined area including the contact position and the sensor electrodes 11, 12.

Description

  The present invention relates to a touch panel cover material and a touch panel using the cover material, for example, a touch panel cover material made of glass or polyethylene terephthalate (PET), and a touch panel using the cover material.

In recent years, in portable information terminals such as smartphones and tablet PCs that are rapidly spreading, a projection capacitive touch panel capable of multi-touch operation is often used.
The structure of the projected capacitive touch panel will be briefly described with reference to FIG. 7 (exploded view). The capacitive touch panel 50 shown in FIG. 7 has an indium tin oxide film (hereinafter referred to as an ITO film) having a plurality of electrodes for detecting coordinates in the Y direction on the back side of a transparent insulating film 53, for example. 51 is formed, and an ITO film 52 having a plurality of electrodes for detecting coordinates in the X direction is formed on the front side.

The ITO film 51 is provided with a plurality of rhombic electrode pads 54 (sensor electrodes) connected in the X direction and electrically connected to each other in the Y direction, and the ITO film 52 is formed in the Y direction. A plurality of rhombic electrode pads 55 (sensor electrodes) connected to each other and electrically connected to each other are provided in a plurality of rows in the X direction. Each of the electrode pads 54 and 55 has a sufficient area to generate a change in capacitance (about 1 pF) that can detect the contact position of a stylus pen (finger, stylus pen, etc.). The width is about 5 mm.
When the insulating film 53 on which the ITO films 51 and 52 are formed is viewed in plan, the electrode pads 54 and 55 have a two-dimensional lattice structure in which the electrode pads 54 and 55 are arranged in the plane direction with a predetermined gap as shown in FIG. ing.

For example, when a fingertip is brought into contact with a cover material (not shown) made of glass or polyethylene terephthalate (PET) disposed on the upper surface of the touch panel 50, the electrode pads 54 connected in the X direction are contacted. Among these, the capacitance of the electrode pad 54 at the contact position changes to a predetermined value or more. Thereby, the coordinate position in the Y direction is detected.
In addition, among the electrode pads 55 connected in the Y direction, the capacitance of the electrode pad 55 at the contact position changes to a predetermined value or more. Thereby, the coordinate position in the X direction is detected.

By the way, the capacitance type touch panel 50 cannot detect the position unless the capacitance (about 1 pF) is changed more than a predetermined value at the contact point by the finger or the stylus pen as described above. .
For this reason, conventionally, an input operation to the capacitive touch panel is performed with a conductive stylus pen or a fingertip that can be contacted with a contact area larger than the area of the electrode pads 54 and 55, and the static operation necessary for position detection is performed. The capacitance is changed (if the contact area is small, the capacitance required for position detection does not change).
For example, Patent Document 1 discloses a prior art regarding a projected capacitive touch panel.

JP 2008-310551 A

However, when inputting to the capacitive touch panel with the conductive stylus pen, the pen tip is thick (for example, 5 mm in diameter (contact area is about 19.6 mm ² ) or more) as described above. Therefore, there is a problem that operability, visibility during operation, and usability are impaired.
In order to solve the above-mentioned problem, it is conceivable to simply subdivide the sensor electrodes of the touch panel and reduce the amount of change in capacitance that can be detected in each sensor electrode. There has been a problem that detection has to be performed and there is a greater risk of erroneous detection.
Further, when the sensor electrodes are subdivided, the number of electrodes increases, so that the amount of calculation for obtaining the touch position greatly increases. Therefore, when the processing capability of the control unit that performs the calculation is insufficient, there is a problem that the touch position detection cannot follow the touch operation, the display is delayed, and the usability is reduced. In addition, when the processing capability of the control unit is improved so that the touch position detection can follow the touch operation, there are problems that the power consumption increases and the cost increases.

The present invention has been intensively studied on improving the cover material in solving the above-described problems, and can detect the touch position even if the contact area of the stylus pen is smaller than the conventional contact area. As a result, the present invention has been completed.
Accordingly, an object of the present invention is to provide a touch panel cover material capable of detecting the contact position even when the contact area of the stylus pen is smaller than the conventional contact area, and a touch panel using the cover material. There is.

In order to solve the above-described problems, a touch panel cover material according to the present invention is a touch panel cover material interposed between a capacitive touch panel in which sensor electrodes are arranged and a conductive stylus pen. When a cover layer has a resistance layer including at least a transparent conductive thin film layer having a predetermined surface resistivity set in a range of 10 ^5.4 to 10 ^7.1 Ω / sq on the substrate surface, and the stylus pen contacts A change in capacitance of 0.45 to 5.29 pF / mm ² per unit area occurs between the predetermined area including the contact position and the sensor electrode.

According to the cover material for a touch panel according to the present invention, the resistance including at least a transparent conductive thin film layer having a predetermined surface resistivity set in a range of 10 ^5.4 to 10 ^7.1 Ω / sq on the substrate surface of the cover material. Since the capacitance change of 0.45 to 5.29 pF / mm ² per unit area occurs between the sensor electrode and the predetermined region including the contact position and the sensor electrode, the contact area of the stylus pen Even if it is smaller than the area of the sensor electrode constituting the touch panel, the area can be increased in a pseudo manner, and a contact state equivalent to a human finger can be obtained.
That is, even if the contact area of the stylus pen is small, it is possible to cause a capacitance change within a predetermined range between the stylus pen in contact with the cover material surface and the sensor electrode, and to change the contact position of the stylus pen. Can be detected.
For this reason, for example, the touch panel can be operated with a stylus pen having a thin pen tip, and operability, visibility during operation, and usability can be improved. Moreover, since the structure of a touch panel can employ | adopt the conventional structure, the increase in the cost concerning manufacture can be suppressed.

Here, in the case of a transparent conductive thin film layer having a surface resistivity exceeding 10 ^7.1 Ω / sq, the area required for detection is electrically connected from the contact position on the touch panel (for example, a finger: about φ10 mm). Therefore, the time constant becomes large, and it is impossible to increase the area sufficiently in a pseudo manner within the detection time of the touch panel. On the other hand, in the case of a transparent conductive thin film layer having a surface resistivity of less than 10 ^5.4 Ω / sq, a range larger than the area necessary for detection is electrically connected within the detection time of the touch panel, and the pseudo area is expanded. Is excessively large, which is not preferable.
In addition, when the capacitance per unit area is less than 0.45 pF / mm ² , the change in capacitance is small and the touch panel does not react unless the contact area with the stylus pen is increased. When the capacitance exceeds 5.29 pF / mm ² , the capacitance per unit area becomes too large, the time constant increases, and charging / discharging performed at the time of detection of the touch panel cannot be performed sufficiently, which is not preferable.

The cover material for a touch panel according to the present invention has a transparent conductive thin film layer formed on the surface of the cover material. However, if a transparent conductive thin film layer is formed on the back side of the cover material, a new design of the touch panel is required. As a matter of course, a thick cover material is interposed between the transparent conductive thin film layer and the stylus pen, which can cause a predetermined capacitance change when operating with a touch pen with a thin pen tip. This is not possible, and the effect of expanding the pseudo area cannot be obtained.
For this reason, by forming the transparent conductive thin film layer on the cover material surface side, it becomes possible to electrically connect the touch panel sensor electrode and the indicator with a predetermined capacitance, and the touch pen with a thin nib. But it becomes possible to operate.

Moreover, it is desirable that the base of the cover material is made of glass or polyethylene terephthalate.
Moreover, it is desirable that the glass has a thickness of 0.26 mm to 1 mm.
When the thickness of the glass exceeds 1 mm, the stored electrostatic capacity is reduced, the change in the electrostatic capacity generated between the pen tip that contacts the cover material surface and the sensor electrode is small, and the contact position of the stylus pen is determined. If the diameter of the stylus pen cannot be detected or the stylus pen is not enlarged, the touch panel does not react.
On the other hand, when the glass thickness is less than 0.26 mm, the stored electrostatic capacity increases, so the time constant related to charging / discharging increases, and a small-diameter stylus pen is sufficient within the detection time of the touch panel. There is an adverse effect that charging / discharging cannot be performed and the touch panel does not react. Moreover, when the thickness of the said glass is less than 0.26 mm, mechanical strength is weak and there exists a possibility of damaging.

  The resistance layer preferably includes a transparent protective layer provided on the transparent conductive thin film layer. By providing the protective layer, the durability of the cover material can be improved.

Further, the touch panel according to the present invention is a touch panel using the touch panel cover material, and the touch panel cover material and sensor electrodes arranged in a lattice shape provided below the touch panel cover material; It is desirable to provide.
According to this touch panel, even when the contact area of the stylus pen, which is a stylus pen, is smaller than the area of the sensor electrode constituting the touch panel (for example, about 12.5 mm ² ), the contact state is equivalent to a human finger. It can be. In other words, even if the contact area of the stylus pen tip is small, a change in capacitance within a predetermined range can be caused between the pen tip that contacts the cover material surface and the sensor electrode. The contact position can be detected.
For this reason, the touch panel can be operated with a stylus pen having a thin pen tip, and operability, visibility during operation, and usability can be improved. Moreover, since the structure of a touch panel can employ | adopt the conventional structure, the increase in the cost concerning manufacture can be suppressed.
The contact area of the nib on the touch panel cover material is preferably 7.1 mm ² or less (the diameter of the stylus pen nib is 3 mm or less).

  ADVANTAGE OF THE INVENTION According to this invention, even if the contact area of a stylus pen is a contact area smaller than the conventional case, the touch panel cover material which can detect a contact position, and the touch panel using the cover material can be obtained. .

FIG. 1 is a cross-sectional view of a touch panel device provided with a cover material for a touch panel according to the present invention. FIG. 2 is a cross-sectional view illustrating a configuration for explaining an effect that an actual contact area is increased in a pseudo manner when a stylus pen having conductivity is brought into contact with a cover material. FIG. 3 is an equivalent circuit of the integration circuit generated in the cover material shown in FIG. FIG. 4 is a side view showing the tip of the stylus pen according to the present invention. 5 is a cross-sectional view schematically showing a state in which the stylus pen of FIG. 4 is brought into contact with the touch panel cover material of FIG. FIG. 6 is a perspective view showing a configuration for capacitance measurement used in Experiment 1 of the example. FIG. 7 is an exploded view schematically showing a configuration of a conventional touch panel. FIG. 8 is a plan view schematically showing sensor electrodes of the touch panel of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a touch panel device provided with a cover material according to the present invention.

  In the touch panel device 1 of FIG. 1, a touch panel 3 is provided on an LCD unit 2 which is a liquid crystal display device, and a cover material 4 which is a dielectric is provided thereon. The cover material 4 is provided with a resistance layer 5.

The touch panel 3 has sensor electrodes made of an ITO film on the front and back surfaces of a transparent insulating film 10 (corresponding to the insulating film 53 in FIG. 7), for example, similarly to the configuration shown in FIG. Specifically, a plurality of electrode pads 11 (corresponding to the electrode pad 55 in FIG. 7) are formed on the front side of the insulating film 10, and a plurality of electrode pads 12 (corresponding to the electrode pad 54 in FIG. 7) are formed on the back side. ing.
Each of the electrode pads 11 and 12 is formed in a rhombus shape similarly to the conventional configuration of FIGS. 7 and 8, thereby constituting a two-dimensional lattice sensor electrode (similar to the configuration of FIG. 8). . Further, the width of the diagonal line of each electrode pad 11, 12 is formed to 5 mm, for example, and a stylus pen (finger or conductive stylus pen) in the electrode pad 11, 12 is changed by a change in predetermined capacitance (for example, about 1 pF). Etc.) can be detected.

The resistance layer 5 includes a transparent conductive thin film layer 6 formed on the cover material 4 and a protective layer 7 formed on the transparent conductive thin film layer 6. The transparent conductive thin film layer 6 The surface resistivity is set in the range of 10 ^5.4 to 10 ^7.1 Ω / sq.

The transparent conductive thin film layer 6 is formed by, for example, forming an ITO film on the upper surface of the cover base 4 made of glass or polyethylene terephthalate by sputtering or the like, or by forming a transparent conductive resin by coating or the like. A film is formed to have a predetermined thickness (for example, a thickness of 0.1 μm to 1 μm).
Such a surface conductive transparent conductive thin film layer 6 is formed by, for example, reducing the film thickness of a conductive polymer represented by an ITO film or polythiophene having low resistance, and increasing the resistivity, Covers low-conductivity grades of conductive polymers such as PEDOT-PSS aqueous solution consisting of a mixture of polymer PEDOT (poly (3,4-ethylenedioxythiophene)) and polyanion PSS (polystyrene sulfonate) It can be obtained by uniformly forming a film on the substrate 4.

The protective layer 7 is formed with a predetermined thickness (for example, a thickness of several μm to several tens of μm) and is made of a transparent resin having high scratch resistance.
Specifically, the protective layer 7 is a hard coating agent that is generally commercially available, for example, trade name: Acier-PMMA (manufactured by Nidec Co., Ltd.) or trade name: purple light UV7600B (Nippon Synthetic Chemical Industry Co., Ltd.). For example, a product name: ORMECON (manufactured by Nissan Chemical Industries, Ltd.), etc., is dispersed about 10%, and is uniformly applied on the transparent conductive thin film layer 6 using a spin coater or a bar coater. It can be obtained by curing with UV light after coating.

In addition, using a hard coat agent having conductivity in advance, for example, trade name: conductive coat UV (manufactured by Chukyo Yushi Co., Ltd.) or trade name: conductive hard coat ink (manufactured by Resino Color Industry Co., Ltd.), etc., the specified resistivity Alternatively, a hard coat agent may be prepared and applied to the upper surface of the cover base 4.
Since the layer formed on the surface of the cover substrate 4 in this manner has the functions of the transparent conductive thin film layer 6 and the protective layer 7, the step of forming the protective layer 7 is eliminated and the thickness is reduced. It is advantageous for ensuring transparency.

Further, the surface resistivity of the transparent conductive thin film layer 6 is within the range of 10 ^5.4 to 10 ^7.1 Ω / sq, and the thickness of the cover base 4, the transparent conductive thin film layer 6, the protective layer 7, and the relative dielectric constant thereof. Accordingly, the change in capacitance per unit area that occurs when the stylus pen comes into contact is set to be 0.45 pF / mm ² or more and 5.29 pF / mm ² or less.

Next, by providing the resistance layer 5 on the cover base 4, it is possible to obtain an effect that the actual contact area is increased in a pseudo manner when a conductive stylus pen is brought into contact with the resistance layer 5. The principle that can be done will be described. A case where a protective layer is not provided will be described.
As shown in FIG. 2, a cover material 20 comprising a transparent conductive thin film layer 21 having a uniform predetermined surface resistivity and a cover base 22 on which the transparent conductive thin film layer 21 is formed is prepared. An electrode 23 having an area larger than that of the cover material 20 is disposed on the lower surface of the cover material 20, and the tip of the conductive stylus pen having an area smaller than that of the cover material 20 (the electrode 24) is disposed on the transparent conductive thin film layer 21. ).

At this time, the cover member 20 sandwiched between the electrodes 23 and 24 can be replaced with an equivalent circuit as shown in FIG. That is, the cover member 20 has a resistance R (R1, R2, R3,..., Rn, Rn + 1,...) And a capacitance C (C1, C2, C3,..., Cn, Cn + 1,. ..) Are distributed (n is a positive integer value).
Here, the time constant τ of the integration circuit is expressed by the following equation (1). As the n of Cn increases (the area increases), the combined value of the resistors connected in series increases and the time constant τ of Cn increases. Becomes bigger.

(Equation 1)
τ = R × C (1)
If the time constant τ becomes too large, Cn can hardly store charges in a short time. Therefore, C1 to Cn-1 are regarded as a range in which capacitance is accumulated.

In such an integration circuit, if the surface resistivity R of the transparent conductive thin film layer 21 is reduced, the time constant τ is reduced from the above equation (1). Therefore, the Cn at the boundary where the electrostatic capacity can be accumulated can be increased to Cn + 1, Cn + 2,..., And the pseudo area can be expanded.
On the other hand, if the capacitance C is reduced, the time constant τ is reduced from the equation (1). Therefore, the Cn at the boundary where the electrostatic capacity can be accumulated can be increased to Cn + 1, Cn + 2,..., And the pseudo area can be expanded.

  In general, the capacitance C can be defined by the following equation (2), so that the time constant τ is also affected by the relative dielectric constant and thickness dimension of the cover base 22.

(Equation 2)
C = εr · ε0 × S / d (2)
εr: relative dielectric constant ε0: vacuum dielectric constant d: dielectric thickness S: electrode area

  Thus, the capacitance C also changes depending on the relative dielectric constant εr and the thickness d of the dielectric. Therefore, when the surface resistivity (resistance R) that functions to enlarge the pseudo area is specified, the capacitance per unit area that the touch panel can react within the range of the surface resistivity (resistance R). It is desirable to define the range at the same time.

A specific range of the surface resistivity and the capacitance per unit area is determined by an actual measurement value using the measuring apparatus shown in FIG. In addition, since the structure shown in FIG. 6 includes the same structure as that already described with reference to FIG. 2, the corresponding members are denoted by the same reference numerals.
In order to determine the range of the surface resistivity and capacitance, first, as shown in FIG. 2, a resistance layer (transparent conductive thin film layer 21) is formed on the surface of a cover base 22 having a square shape of 80 mm × 80 mm. The cover material 20 is prepared.
As shown in FIG. 6, this cover material 20 is disposed on a 100 mm × 100 mm square aluminum electrode 23, and further on that, a cylindrical shape having a diameter of 8.0 mm (contact area is 50.24 mm ² ). The copper electrode 24 is arranged. The area of a circle with a diameter of 8.0 mm is substantially equal to the area when a human finger contacts the touch panel.

In the actual measurement in the measuring apparatus of FIG. 6, an LCR meter 25 (U1731 manufactured by Agilent) is connected to the electrodes 23 and 24 as a measuring instrument, and the surface resistivity of the transparent conductive thin film layer 21 is set as a plurality of conditions. The capacitance generated in the cover material 20 is measured at a measurement frequency of 1 kHz. The measured electrostatic capacity is divided by the contact area 50.24 mm ² of the electrode 24 to determine the electrostatic capacity per unit area.
Thereafter, a stylus pen is brought into contact with the cover material 20 to check whether the touch panel reacts.
Thereby, when the stylus pen having a predetermined diameter comes into contact, the surface resistivity of the cover material and the capacitance range per unit area to which the touch panel reacts can be obtained.

As a result of the measurement, when a transparent conductive thin film layer having a surface resistivity of 10 ^5.4 to 10 ^7.1 Ω / sq is provided and the capacitance per unit area is 0.45 to 5.29 pF / mm ² , It was confirmed that the touch panel reacts even when the diameter of the stylus pen is 3 mm, which does not react, and an effect that the actual contact area is increased in a pseudo manner can be obtained.
As described above, when the cover material includes a transparent conductive thin film layer having a surface resistivity of 10 ^5.4 to 10 ^7.1 Ω / sq and a capacitance per unit area is 0.45 to 5.29 pF / mm ^2. Can use a stylus pen with a smaller diameter than the pen tip of a conventional stylus pen, and can improve operability, visibility during operation, and usability.

Next, the configuration of the stylus pen used with the cover material having the resistance layer 5 shown in FIG. 1 will be described with reference to FIG. FIG. 4 is a side view showing the tip of the stylus pen 30 according to the present invention.
The stylus pen 30 shown in FIG. 4 has a pen tip 31 formed of a conductive material (for example, steel, copper, conductive rubber, conductive fiber, etc.), and a pen tip holder 32 that holds the pen tip 31. . On the rear end side from the pen tip holder 32, a grip portion, a pen shaft main body, and the like (both not shown) are provided.

  The pen tip holder 32, the grip portion, the pen shaft main body, and the like are made of a conductive material (for example, an aluminum alloy) electrically connected to the pen tip 31 so as to electrically couple the human body and the pen tip 31. Is formed. Alternatively, for example, a metal conduction portion (not shown) in which a hand (finger) of a pen user (human body) is in contact with the surface of the pen tip holder 32, the grip portion, the pen shaft main body, or the like is used. You may provide in the state electrically connected with 31.

The tip width dimension d1 of the pen tip 31 is formed to be smaller than the width of the diagonal lines (for example, 5 mm) of the electrode pads 11 and 12 of the touch panel 3.
Specifically, the tip width dimension (diameter) d1 of the nib 31 is preferably smaller than the nib of the conventional stylus pen and 3 mm or less in diameter, and the contact area of the nib on the touch panel cover material is as follows: It is desirable that it is 7.1 mm ² or less.
The stylus pen according to the present invention is not limited to the shape shown in FIG. That is, when the pen user uses the stylus pen 30 in his / her hand, the tip user is provided with a pen tip which is formed of at least a conductive material and whose tip width is smaller than the width of the electrode pads 11 and 12. It is sufficient if the hand and the pen tip are electrically coupled.

As shown in FIG. 5, when the stylus pen 30 contacts the resistance layer 5, the transparent conductive thin film layer 6 included in the resistance layer 5 has a surface resistivity set in the range of 10 ^5.4 to 10 ^7.1 Ω / sq. Therefore, the contact area of the stylus pen 30 that is a conductor is increased in a pseudo manner, and a state equivalent to a case where a human fingertip comes into contact is obtained.
In addition, since the capacitance per unit area is at least 0.45 pF / mm ² , the contact area of the pen tip on the touch panel cover material is 7.1 mm ² (diameter 3 mm). The capacitance becomes 3.2 pF, a change in capacitance (about 1 pF) can be generated, and the position can be detected.
When the contact area of the pen tip on the touch panel cover material is 2.2 mm ² (diameter 1.7 mm), the capacitance is 1 pF, and detecting the position is the detection limit value.
Accordingly, the nib of the stylus pen preferably has a diameter of about 1.7 mm to 3 mm in consideration of ease of use.

As shown in FIG. 5, in a predetermined region including the contact position of the pen tip 31 of the stylus pen 30, there is a gap between the resistance layer 5 and the electrode pad 11 (the cover base 4 that is a dielectric (glass)). A predetermined capacitance change occurs per unit area.
The capacitance generated between the resistance layer 5 and the electrode pad 11 flows as a weak current (for example, 10 μA to 20 μA) to the human body via the stylus pen 30, and thereby the contact of the pen tip 31 of the stylus pen 30. Among the positions, for example, a vertical coordinate position (a position in the Y direction in FIGS. 7 and 8) is detected.

Further, as in the case of the transparent conductive thin film layer 6 and the electrode pad 11, between the transparent conductive thin film layer 6 and the electrode pad 12 (dielectric (glass)) at the contact position of the pen tip 31 of the stylus pen 30. A certain change in capacitance per unit area also occurs in a certain cover substrate 4).
The electrostatic capacitance generated between the resistance layer 56 and the electrode pad 12 flows as a weak current (for example, 10 μA to 20 μA) to the human body via the stylus pen 30, thereby causing the pen tip 31 of the stylus pen 30 to flow. Among the contact positions, for example, the coordinate position in the horizontal direction (the position in the X direction in FIGS. 7 and 8) is detected.

As described above, according to the embodiment of the present invention, the resistance including the transparent conductive thin film layer 6 whose surface resistivity is set in the range of 10 ^5.4 to 10 ^7.1 Ω / sq on the surface of the cover base 4. Since the layer 5 is provided and the capacitance per unit area is 0.45 to 5.29 pF / mm ² , the contact area of the stylus pen 30 is smaller than the area of the electrode pads 11 and 12 constituting the touch panel 3. Also, the contact area can be increased in a pseudo manner.
A predetermined capacitance change per unit area occurs between the transparent conductive thin film layer 6 of the resistance layer 5 and the electrode pads 11 and 12, so that the contact state is equivalent to a human finger. Can do. That is, even if the contact area of the pen tip 31 of the stylus pen 30 is small, it is necessary for the reaction of the touch panel 3 between the pen tip 31 in contact with the surface of the resistance layer 5 and the electrode pads 11 and 12 (cover base 4). A change in electrostatic capacitance can be caused, and the contact position of the stylus pen 30 can be detected.

  As a result, the touch panel device 1 can be operated with the stylus pen 30 having a thin pen tip 31, and the operability, visibility during operation, and usability can be improved. Moreover, since the structure of the touch panel 3 can employ | adopt the conventional structure, it can suppress the increase in the cost concerning manufacture.

  Moreover, in the said embodiment, although the transparent conductive thin film layer 6 demonstrated as what was formed, for example by an ITO film | membrane etc., not only it but what kind of material will be used if it has transparency and electroconductivity. May be formed. In addition, the transparency in the transparent conductive thin film layer 6 and the protective layer 7 described in the above embodiment refers to a state in which the content of the display image can be identified when it is disposed on the touch panel.

  In the above-described embodiment, the projected capacitive touch panel has been described as an example. However, the present invention is not limited to this, and a capacitive capacitive touch panel that detects a change in weak current due to the contact of the pen tip and detects the position. Any touch panel can be applied.

[Experiment 1]
In Experiment 1, the surface resistivity of the transparent conductive thin film layer was changed, and the value of the capacitance per unit area with respect to the surface resistivity was obtained, and whether or not the actual touch panel responded was verified. In addition, the resistance layer used in the following examples was configured not to include a protective film formed on the upper surface of the transparent conductive thin film layer.

First, a cover material 20 is prepared in which a transparent conductive thin film layer 21 having a uniform predetermined surface resistivity is formed on the surface of a cover base 22 made of 80 mm × 80 mm square glass (see FIG. 2). .
The cover base 22 is made of chemically strengthened glass whose surface is strengthened by an ion exchange strengthening method or the like generally used in information terminals (touch panels), and has a thickness of 1 mm and a relative dielectric constant of 7.2. Using.

As shown in FIG. 6, this cover member 20 is arranged on a 100 mm × 100 mm square aluminum electrode 23, and a circle having a diameter of 8.0 mm (contact area is about 50.3 mm ² ) is further formed thereon. A columnar copper electrode 24 is disposed.
Note that the area of the circle having a diameter of 8.0 mm is substantially equal to the area when a human finger contacts the touch panel.

  In Experiment 1, a plurality of cover materials 20 having different surface resistivity of the transparent conductive thin film layer 21 were formed (Sample Nos. 1 to 13). Specifically, the transparent conductive thin film layer 21 is mainly composed of polythiophene, which is a conductive polymer, and is applied so as to have a thickness of 0.5 to 1 μm, and the content of polythiophene, which is a conductive material, is changed. Transparent conductive thin film layers 21 having different surface resistivity were prepared. Then, the capacitance generated between the electrodes 23 and 24 was measured for each cover member 20 having a different surface resistivity 1 by using the measuring device of FIG.

An LCR meter 35 (Agilent U1733) was connected to the electrodes 23 and 24 as a measuring instrument, and the capacitance generated in the cover material 20 was measured at a measurement frequency of 1 kHz.
Then, the capacitance was divided by the contact area of 50.3 mm ² to obtain the capacitance per unit area. The results are shown in Table 1.

  In addition, each cover material 20 having a different surface resistivity 1 was verified using a fifth generation eye pad (registered trademark) to which the touch panel reacts. The results are shown in Table 1.

In this verification, the nib is made of conductive rubber (2.5 Ω · cm), and the nib holder, grip part, and pen shaft body are electrically connected to the nib 31 (aluminum alloy). The stylus pen formed by was used.
In addition, when the fifth generation eye pad (registered trademark) is purchased (when the cover material according to the present invention is not attached), when the pen tip diameter of the stylus pen is 4 mm, the touch panel Although it reacted, it did not react when the diameter was 3 mm. Therefore, the diameter of the pen tip of the stylus pen was set to 3 mm.
The results are shown in Table 1. In Table 1, “X” in the column of the stylus pen reaction indicates no reaction, and “◯” indicates the reaction.

Further, as a comparative example, a cover material 20 that does not form a transparent conductive thin film layer is prepared on the surface of a cover base 22 made of 80 mm × 80 mm square glass, and the surface resistivity, capacitance per unit area, The stylus pen response was verified.
As a result, the surface resistivity was 10 ¹² Ω / sq, the capacitance per unit area was 0.19 pF / mm ² , and the stylus pen with a diameter of 3 mm did not react.

From Experiment 1, when a transparent conductive thin film layer having a surface resistivity of 10 ^5.4 to 10 ^7.1 Ω / sq is provided and the capacitance per unit area is 0.45 to 2.44 pF / mm ² , Even when the diameter of the stylus pen, which does not react normally, is 3 mm, it was confirmed that the touch panel reacted and the diameter of the pen tip of the stylus pen could be reduced.

[Experiment 2]
In Experiment 2, the thickness 1 mm of the chemically strengthened glass of the cover base 22 in Experiment 1 was changed to 0.26 mm (Sample No. 14 to No. 26), and other conditions were the same as in Experiment 1. Experimented.
The results are shown in Table 1. In Table 1, “X” in the column of the stylus pen reaction indicates no reaction, and “◯” indicates reaction.

From Experiment 2, when a transparent conductive thin film layer having a surface resistivity of 10 ^5.4 to 10 ^7.1 Ω / sq is provided and the capacitance per unit area is 0.50 to 5.29 pF / mm ² , Usually, even when the diameter of the stylus pen that does not react is 3 mm, the touch panel reacts, and it was confirmed that the diameter of the pen tip of the stylus pen can be reduced.

From the results of the above experiments 1 and 2, the cover substrate is made of glass, further provided with a transparent conductive thin film layer having a surface resistivity of 10 ^5.4 to 10 ^7.1 Ω / sq, and a capacitance per unit area of 0.45 to When it was 5.29 pF / mm ² , it was found that even when the diameter of the stylus pen is 3 mm, which does not normally react, the touch panel reacts and the diameter of the stylus pen nib can be reduced. .

Next, experiments 3 and 4 were performed and verified for the case where the cover substrate was polyethylene terephthalate (PET).
[Experiment 3]
In Experiment 3, polyethylene terephthalate (PET) was used as the cover substrate, and the other conditions were the same as those in Experiment 1. The cover substrate having a thickness of 1 mm and a relative dielectric constant of 3.0 was used.

  Also in Experiment 3, a plurality of cover materials 20 having different surface resistivity of the transparent conductive thin film layer 21 were formed (Sample Nos. 27 to 38). Specifically, the transparent conductive thin film layer 21 is mainly composed of polythiophene, which is a conductive polymer, and is applied so as to have a thickness of 0.5 to 1 μm, and the content of polythiophene, which is a conductive material, is changed. Transparent conductive thin film layers 21 having different surface resistivity were prepared. Then, the capacitance generated between the electrodes 23 and 24 was measured for each cover member 20 having a different surface resistivity 1 by using the measuring device of FIG.

An LCR meter 35 (Agilent U1733) was connected to the electrodes 23 and 24 as a measuring instrument, and the capacitance generated in the cover material 20 was measured at a measurement frequency of 1 kHz.
Then, the capacitance was divided by the contact area of 50.3 mm ² to obtain the capacitance per unit area. The results are shown in Table 3.

  In addition, each cover material 20 having a different surface resistivity 1 was verified using a fifth generation eye pad (registered trademark) to which the touch panel reacts. The results are shown in Table 3.

In this verification, the nib is made of conductive rubber (2.5 Ω · cm), and the nib holder, grip part, and pen shaft body are electrically connected to the nib 31 (aluminum alloy). A stylus pen with a pen tip diameter of 3 mm was used.
The results are shown in Table 1. In Table 3, “X” in the column of the stylus pen reaction indicates no reaction, and “◯” indicates the reaction.

From Experiment 3, when a transparent conductive thin film layer having a surface resistivity of 10 ^5.4 to 10 ^7.1 Ω / sq is provided and the capacitance per unit area is 0.65 to 1.85 pF / mm ² , Even when the diameter of the stylus pen, which does not react normally, is 3 mm, it was confirmed that the touch panel reacted and the diameter of the pen tip of the stylus pen could be reduced.

[Experiment 4]
In Experiment 4, the thickness of 1 mm of the polyethylene terephthalate (PET) of the cover base of Experiment 3 was changed to 0.26 mm (Sample No. 39 to No. 50), and other conditions were as in Experiment 1, Experiment 3 Experiments were performed under the same conditions.
The results are shown in Table 4. In Table 4, “X” in the column of stylus pen reaction indicates no reaction, and “◯” indicates reaction.

From Experiment 4, when a transparent conductive thin film layer having a surface resistivity of 10 ^5.4 to 10 ^7.1 Ω / sq is provided and the capacitance per unit area is 0.73 to 3.05 pF / mm ² , Usually, even when the diameter of the stylus pen that does not react is 3 mm, the touch panel reacts, and it was confirmed that the diameter of the pen tip of the stylus pen can be reduced.

From the results of the above experiments 3 and 4, the cover substrate is made of glass, further provided with a transparent conductive thin film layer having a surface resistivity of 10 ^5.4 to 10 ^7.1 Ω / sq, and a capacitance per unit area of 0.65 to When it was 3.05 pF / mm ² , it was found that the touch panel reacts even when the diameter of the stylus pen is 3 mm, which does not normally react, and the diameter of the pen tip of the stylus pen can be reduced. .

From the results of Experiments 1 to 4, the substrate of the cover material is made of glass or polyethylene terephthalate, and further includes a transparent conductive thin film layer having a surface resistivity of 10 ^5.4 to 10 ^7.1 Ω / sq. When the capacitance is 0.45 to 5.29 pF / mm ² , the touch panel reacts even when the stylus pen diameter is 3 mm, which does not normally react. It was found that the diameter could be reduced.

1 Touch Panel Device 2 LCD Unit 3 Touch Panel 4 Cover Base (Cover Material)
5 Resistance layer (cover material)
6 Transparent conductive thin film layer (cover material)
7 Protective layer (cover material)
10 Insulating film 11 Electrode pad (sensor electrode)
12 Electrode pads (sensor electrodes)
30 Stylus pen 31 Nib 32 Nib holder (conduction part)

Claims (5)

In the touch panel cover material interposed between the capacitive touch panel in which the sensor electrode is disposed and the conductive stylus pen,
Having a resistance layer including at least a transparent conductive thin film layer having a predetermined surface resistivity set in a range of 10 ^5.4 to 10 ^7.1 Ω / sq on the surface of the cover material;
When the stylus pen comes into contact, a capacitance change of 0.45 to 5.29 pF / mm ² per unit area occurs between a predetermined region including the contact position and the sensor electrode. Cover material for touch panel.   2. The touch panel cover material according to claim 1, wherein the base of the cover material is made of glass or polyethylene terephthalate.   The cover material for a touch panel according to claim 2, wherein the glass has a thickness of 0.26 mm to 1 mm.   The touch panel cover material according to claim 1, wherein the resistance layer includes a transparent protective layer provided on the transparent conductive thin film layer. A touch panel using the touch panel cover material according to any one of claims 1 to 4,
A capacitive touch panel, comprising: the touch panel cover material; and sensor electrodes arranged below the touch panel cover material and arranged in a grid pattern.

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