JP6566239B2 - Stylus pen for capacitive touch panel - Google Patents

Description

The present invention relates to a stylus pen used for a touch panel, and more particularly to a stylus pen used for a capacitive touch panel.

2. Description of the Related Art In recent years, in a portable information terminal that is rapidly spreading, for example, a smart phone or a tablet-type personal computer, a capacitive touch panel capable of a touch operation is often used. In a capacitive touch panel, a weak current generated when a finger or the like touches the screen, that is, a change in capacitance is sensed by a sensor to sense a touch position. There are two types of capacitance type touch panel structures, a surface type and a projection type.

The surface type is used for a relatively large panel, and has a structure in which a transparent electrode film is provided on a glass substrate and a protective layer is provided on the surface of the transparent electrode film. By applying a voltage to the electrodes provided at the four corners of the glass substrate, a uniform low-voltage electric field is generated throughout the panel, and the change in capacitance when the finger touches is detected at the four corners of the glass. The coordinates of are specified. The surface type is simpler and less expensive than the projection type, but it is difficult to detect two or more points simultaneously.

On the other hand, in the projection structure, a large number of transparent electrodes are arranged in a specific pattern on a substrate on which an IC that can perform arithmetic processing is mounted, and a cover of an insulator such as glass or transparent plastic is overlaid on the electrode surface. The projection type touch panel is described in Patent Document 1, for example. When a finger or the like is brought into contact with the cover surface, the capacitance changes simultaneously between the plurality of electrodes, and the contact position can be sensed with high accuracy by measuring this current ratio. For this reason, the projection type enables accurate multipoint sensing (so-called multitouch). The projection type is often used for a screen smaller than the surface type, and in recent years, a multi-touch operation with high-speed response and high accuracy is possible in a portable device.

By the way, since it is necessary to change the capacitance in order to sense a capacitive touch panel, the touch position must be set correctly unless a dedicated stylus pen is used for both surface and projection types. It cannot be perceived. In addition, the capacitance type touch panel cannot be sensed unless a change in capacitance (about 1 pF) greater than or equal to a predetermined value is generated at a contact location with a finger or a stylus pen.

For this reason, conventionally, a conductive stylus pen is used for an input operation on a capacitive touch panel, and a change in capacitance necessary for position detection is generated.

The change in capacitance flows as a weak current (approximately 10 μA to 20 μA) to the human body via the stylus pen, whereby the touch panel touch position of the stylus pen tip is sensed. Therefore, conventionally, a stylus pen uses one end of a conductive shaft as a pen tip. Also, as illustrated in Patent Documents 2, 3 and 4, the pen tip made of a conductive resin fiber bundle, conductive rubber, or the like, as exemplified in Patent Documents 2, 3 and 4, so as not to damage the touch panel surface with the pen tip. Or a nib covered with a conductive cloth has been proposed.

On the other hand, in recent portable terminals, more delicate operations are often required. In a portable terminal using a capacitive touch panel, in order to perform a more delicate operation, it is necessary to improve the sensing performance of the stylus pen with respect to the touch panel. If the sensing performance of the stylus pen on the touch panel is poor, the content intended by the user cannot be input to the mobile terminal. In other words, if the stylus pen's tip is brought into contact with the touch panel, the user intends to input the content intended by the user into the mobile terminal, but the touch panel is input by the stylus pen when the stylus pen's sensing performance is poor. Cannot be detected, and the intended content cannot be input. In order to perform more delicate operations, it is necessary for the touch panel to sense fine movements of the stylus pen, and thus there is an increasing demand for improvement in stylus pen sensing performance for the touch panel.

However, a fiber bundle of conductive resin, which is a conductive material as described in Patent Document 2, a nib made of conductive rubber that is elastically deformed as described in Patent Document 3, and Patent Document In the stylus pen with the pen tip covered with the conductive cloth as described in No. 4, the touch panel cannot sense the stylus pen unless the pen tip is strongly pressed against the surface of the touch panel. For this reason, since the touch panel cannot sense the stylus pen when the pen tip is weakly pressed, these conventional stylus pens are not sufficient in terms of performing more delicate operations.

JP 2008-310551 A JP 2013-050936 A JP2013-214208A JP 2013-065147 A

Therefore, the problem to be solved by the present invention is a stylus pen used for a capacitive touch panel, and it is difficult for the pen tip to scratch the touch panel surface, and the touch panel can be touched only by lightly touching the touch panel. It is to provide a stylus pen that has both a sensing performance capable of sensing the position of the pen tip of the stylus pen with a simple structure.

As a result of intensive studies, the inventors of the present invention used a stylus pen nib with a fiber bundle of conductive resin, which is a conductive material, or a conductive rubber that is elastically deformed, as exemplified in Patent Document 2. Even if it is not manufactured, providing a thin silicone layer on the surface of the stylus pen tip that touches the touch panel makes it difficult for the pen tip to scratch the touch panel surface. The present inventors have found that the performance of detecting the position of the pen tip of the pen hardly decreases, and have come to the present invention. Furthermore, the present inventors have found that the sensing performance of the touch panel with respect to the stylus pen is improved by providing a conductive silicone layer on the surface of the stylus pen that comes into contact with the touch panel of the pen tip. It came to.

1st invention is a stylus pen used for an electrostatic capacitance type touch panel, the thickness of the metal nib surface which contacts a touch panel is 30-150 micrometers, and the ratio of 2 to 5 weight% of carbon nanotubes A stylus pen characterized by having a silicone layer contained in

In the second invention, the silicone rubber used in the silicone layer is obtained by curing a silicone composition comprising a diorganopolysiloxane having two or more alkenyl groups in one molecule and an organohydrogenpolysiloxane by an addition reaction. The diorganopolysiloxane is a linear diorganopolysiloxane having vinyl groups only at both ends, a linear diorganopolysiloxane having vinyl groups at both ends and side chains, and a vinyl group only at the ends. A first invention characterized in that it is crosslinked with at least one silicone selected from a branched diorganopolysiloxane having a branched diorganopolysiloxane having vinyl groups at its terminals and side chains as a main component. The stylus pen described.

According to the present invention, a capacitive touch panel that makes it difficult for the pen tip to scratch the surface of the touch panel and to allow the touch panel to sense the position of the pen tip of the stylus pen by simply touching the pen tip to the touch panel. Further, the stylus pen used in the above can be provided with a simple structure.

Hereinafter, the stylus pen of the present invention will be described in more detail.

(Stylus pen A)
A stylus pen A according to a first embodiment of the present invention is shown in FIG. 1A is a view showing a side appearance of the stylus pen A, FIG. 1B is a cross-sectional view taken along line L1-L1 of FIG. 1A, and FIG. 1C is a view of FIG. It is an enlarged view of M1 part which is a nib part of stylus pen A. The stylus pen of the present invention is for a capacitive touch panel, and refers to a conductive material that is shaped like a writing instrument. The material is not particularly limited as long as it is a conductive material, and as this material, a metal material, a surface-plated material, or a carbon material may be used.

The stylus pen A of the present invention does not need to be entirely made of a conductive material. If the pen tip position of the stylus pen A in contact with the touch panel can be detected by the touch panel, a non-conductive material may be used. Is possible.

(Silicone layer)
In the stylus pen A of the present invention, by providing a thin silicone layer on the surface of the pen tip portion that comes into contact with the touch panel, it becomes difficult for the pen tip to damage the touch panel surface, and the touch panel can be touched by simply touching the pen tip to the touch panel. The position of the pen tip can be sensed.

The silicone layer is mainly composed of silicone rubber, and as the silicone rubber used, for example, at least one kind selected from radical polymerization type, condensation type, addition reaction type, crosslinking type, or ring-opening polymerization type reaction silicone rubber is used. Examples include those obtained by crosslinking silicone rubber, and of these, addition reaction type silicone rubber is preferable. In addition, in the silicone rubber used for the silicone layer, MQ resin or the like may be used as long as the sliding property between the touch panel surface and the pen tip of the stylus pen A is not lowered for the purpose of further preventing the touch panel surface from being damaged. A silicone resin may be contained.

The crosslinking agent used for the crosslinking reaction of the silicone rubber may be a known one, and examples of the crosslinking agent include organohydrogenpolysiloxane.

As the addition reaction type silicone rubber, a silicone composition comprising a diorganopolysiloxane having two or more alkenyl groups in one molecule and an organohydrogenpolysiloxane as a crosslinking agent in that the touch panel surface is hardly damaged. Those obtained by curing by addition reaction are preferred.

Examples of the diorganopolysiloxane having two or more alkenyl groups in one molecule include a silicone composed of a linear diorganopolysiloxane having a vinyl group only at both ends in terms of being hard to damage the touch panel surface, Silicone consisting of a linear diorganopolysiloxane having vinyl groups at the ends and side chains, silicone consisting of branched diorganopolysiloxane having vinyl groups only at the ends, and branches having vinyl groups at the ends and side chains Those obtained by crosslinking at least one silicone selected from silicones composed of diorganopolysiloxane are preferred.

The catalyst used for the crosslinking reaction of the silicone rubber may be a known one, and a platinum-based catalyst is preferably used. Examples thereof include chloroplatinic acid such as chloroplatinic acid and chloroplatinic acid, alcohol compounds of chloroplatinic acid, aldehyde compounds, and chain salts of chloroplatinic acid and various olefins.

The thickness of the silicone layer is preferably in the range of 20 μm to 200 μm, more preferably 30 μm to 150 μm. When the thickness of the silicone layer is less than 20 μm, it is difficult to obtain the effect of making the touch panel difficult to damage the stylus pen A. When the thickness exceeds 200 μm, it becomes difficult to pass a weak current, and the sensing performance of the touch panel with respect to the stylus pen A is deteriorated.

As a method of providing a silicone layer on the pen tip of the stylus pen A, a known method such as a method of applying a silicone rubber dissolved in an organic solvent and adjusting a viscosity, or a method of applying a silicone rubber dispersed in water is used. Of these, the spray coating method is preferable because it is easy to make the thickness of the silicone layer uniform. The silicone layer is formed by heating after laminating on the pen tip by a spray coating method.

(Stylus pen B)
The stylus pen B of the second embodiment of the present invention is the same as the stylus pen A except that the silicone layer is made of conductive silicone.

(Silicone layer)
As a material for forming the silicone layer of the stylus pen B, a material further used for forming the silicone layer of the stylus pen A and further containing a conductive material is used.

As a method for forming the silicone layer of the stylus pen B, a method similar to the method for forming the silicone layer of the stylus pen A can be used.

The preferred thickness of the silicone layer of stylus pen B is similar to the silicone layer of stylus pen A, but since the silicone layer of stylus pen B contains a conductive material, stylus pen B is compared to stylus pen A. , Easily touched by the touch panel.

(Conductive material)
As the conductive material to be included in the material for forming the silicone layer of the stylus pen B, various metal particles such as carbon black, graphite, silver, nickel, copper or the like, various metal oxide particles, various non-conductive particles, and short fiber surfaces Treated with a metal such as silver, or a mixture of one or more of carbon nanotubes, carbon fibers, metal fibers, etc., reduces the volume resistivity of the silicone layer without impairing the properties of the silicone layer Can be used as appropriate. In the stylus pen B, carbon nanotubes, carbon fibers, or various metal particles are preferable among the conductive materials in that the electric resistance of the silicone layer surface serving as the pen tip surface can be further reduced. Among these three types of conductive materials, carbon nanotubes are most suitable because they are easily dispersed in the silicone layer, and the external dimensions are close to the thickness of the silicone layer in that the electrical resistance can be reduced even with a small amount. Metal particles are most preferred.

The content of the conductive material in the silicone layer of the stylus pen B is preferably as much as possible in terms of improving the sensing performance of the touch panel. However, if the content of the conductive material is excessive, the touch panel is easily damaged. If it is a conductive material that can be dispersed in the silicone layer and does not damage the touch panel, it is preferable to contain 1 wt% or more and 30 wt% or less with respect to the entire silicone layer. When carbon nanotubes are used as the conductive material, the carbon nanotubes preferably contain 1% by weight or more and 10% by weight or less, more preferably 2% by weight or more and 5% by weight or less based on the entire silicone layer. . When the content of the carbon nanotube is less than 1% by weight, the conductivity of the silicone layer is small and the effect of improving the sensing performance is poor. On the other hand, when the content of the carbon nanotubes exceeds 10% by weight, the surface of the silicone layer tends to damage the touch panel.

EXAMPLES Hereinafter, although an Example , a reference example, and a comparative example are shown and this invention is demonstrated in detail, this invention is not restrict | limited to the following Example. In the examples , reference examples, and comparative examples, “parts” indicates parts by weight unless otherwise specified.

(Comparative Example 1)
A commercially available stylus pen C shown in FIG. 3 was prepared. FIG. 3A is a diagram showing a side appearance of the stylus pen C, FIG. 3B is a cross-sectional view taken along line L3-L3 of FIG. 3A, and FIG. It is a figure which shows the state which used the stylus pen C for the stylus pen detection evaluation. The stylus pen C has a shaft portion made of aluminum, and a pen tip portion to be brought into contact with the touch panel is made of a dome-shaped conductive silicone rubber. When the pen tip portion of the stylus pen C is pressed against the surface of the touch panel, the conductive rubber is deformed to follow the touch panel surface. The diameter of the dome-shaped conductive rubber is 10 mm.

(Comparative Example 2)
As shown in FIG. 4, the dome-shaped conductive silicone rubber of the stylus pen C was removed, and a cube of aluminum (A5052) having a side of 5 mm was fixed to the stylus pen with solder to obtain a stylus pen D. 4A is a diagram showing a side appearance of the stylus pen D, FIG. 4B is a cross-sectional view taken along line L4-L4 of FIG. 4A, and FIG. 4C is a diagram of FIG. 4B. It is an enlarged view of M4 part which is the front-end | tip part of a stylus pen.

( Reference Example 1 )
The following silicone coating solution is applied by spray coating to the entire tip of the aluminum cube of the stylus pen D shown in FIG. 4 so that the film thickness becomes 120 μm, and heated at 150 ° C. for 100 seconds to form a silicone layer To obtain a stylus pen A1 (shown in FIG. 1).
(Silicone coating solution)
Vinyl group-containing diorganopolysiloxane (average molecular weight 700,000) 68.10 parts Polyorganohydrogensiloxane (average molecular weight 2,000) 0.69 parts Platinum catalyst 1.00 parts Toluene 30.00 parts

( Reference example 2)
A stylus pen was produced in the same manner as in Reference Example 1 except that the silicone coating solution was applied so that the film thickness was 40 μm, to obtain a stylus pen A2.

( Reference Example 3)
A stylus pen was produced in the same manner as in Reference Example 1 except that the silicone coating solution was applied so that the film thickness was 150 μm, to obtain a stylus pen A3.

( Reference Example 4)
A stylus pen was produced in the same manner as in Reference Example 1 except that one side of the legislature was changed to 6 mm to obtain a stylus pen A4.

( Reference Example 5)
A stylus pen was produced in the same manner as in Reference Example 4 except that the silicone coating solution was applied so that the film thickness was 40 μm, to obtain a stylus pen A5.

( Reference Example 6)
A stylus pen was produced in the same manner as in Reference Example 4 except that the silicone coating solution was applied so that the film thickness was 150 μm, to obtain a stylus pen A6.

( Reference Example 7)
A stylus pen was manufactured in the same manner as in Reference Example 1 except that one side of the legislature was set to 7 mm to obtain a stylus pen A7.

( Reference Example 8)
A stylus pen was produced in the same manner as in Reference Example 7 except that the silicone coating solution was applied so that the film thickness was 40 μm, to obtain a stylus pen A8.

( Reference Example 9)
A stylus pen was produced in the same manner as in Reference Example 7 except that the silicone coating solution was applied so that the film thickness was 150 μm, to obtain a stylus pen A9.

(Example 10)
The following conductive silicone coating solution 1 is applied by spray coating to the entire surface of the aluminum cube of the stylus pen D shown in FIG. 4 so that the film thickness becomes 120 μm, and heated at 150 ° C. for 100 seconds. Thus, a silicone layer was formed to obtain a stylus pen B1 (shown in FIG. 2).
(Conductive silicone coating solution 1)
Vinyl group-containing diorganopolysiloxane (average molecular weight 700,000) 68.10 parts polyorganohydrogensiloxane (average molecular weight 2,000) 0.69 parts carbon nanotubes 1.50 parts platinum catalyst 1.00 parts toluene 30.00 Part

Example 11
A stylus pen was produced in the same manner as in Example 10 except that the conductive silicone coating solution 1 was applied so that the film thickness was 40 μm, and a stylus pen B2 was obtained.

(Example 12)
A stylus pen was produced in the same manner as in Example 10 except that the conductive silicone coating liquid 1 was applied so that the film thickness was 150 μm, to obtain a stylus pen B3.

(Example 13)
The following conductive silicone coating solution 2 is applied by spray coating to the entire tip of the aluminum cube of the stylus pen D shown in FIG. 4 so that the film thickness becomes 120 μm, and heated at 150 ° C. for 100 seconds. Thus, a silicone layer was formed to obtain a stylus pen B4 (shown in FIG. 2).
(Conductive silicone coating solution 2)
Vinyl group-containing diorganopolysiloxane (average molecular weight 700,000) 68.10 parts polyorganohydrogensiloxane (average molecular weight 2,000) 0.69 parts carbon nanotubes 3.00 parts platinum catalyst 1.00 parts toluene 30.00 Part

(Example 14)
A stylus pen was produced in the same manner as in Example 13 except that the conductive silicone coating liquid 2 was applied so that the film thickness was 40 μm, and a stylus pen B5 was obtained.

(Example 15)
A stylus pen was produced in the same manner as in Example 13 except that the conductive silicone coating liquid 2 was applied so that the film thickness was 150 μm, to obtain a stylus pen B6.

(Comparative Example 3)
A stylus pen was produced in the same manner as in Reference Example 1 except that the silicone coating solution was applied so that the film thickness was 250 μm, and stylus pen E was obtained.

(Evaluation of ease of scratching the touch panel surface of the stylus pen)
The stylus pens A1, A2, and A3 of Reference Examples 1 to 3, the stylus pens B1, B2, B3, B4, B5, and B6 of Examples 10 to 15, the stylus pen D of Comparative Example 2, and a projection touch panel were provided. A tablet computer was prepared. Moreover, when the stylus pen was held in the holder, a device (see FIG. 5) was prepared that can reciprocate while maintaining the state where the pen tip of the stylus pen is pressed against the touch panel of the tablet computer at a certain angle. Each stylus pen was held in a holder, and the stylus pen was reciprocated in a state where the pen tip pressed the touch panel at 3.0 N, and the presence or absence of a scratch generated on the touch panel was visually confirmed. The reciprocating motion was performed at a speed of reciprocating 60 mm per minute at a moving distance of 50 mm, and after 10,000 reciprocations, the scratches on the touch panel surface were visually confirmed. The results of evaluation were recorded in Table 1 with x indicating scratches and ◯ when scratches were not generated. 5A is a diagram showing a state in which the pen tip of the stylus pen held by the holder of the device that reciprocates presses the touch panel, and FIG. 5B shows the state where the holder of the device that reciprocates moves. FIG. 5C is a diagram illustrating a state in which the pen tip of the stylus pen is lifted away from the touch panel, and FIG. 5C is a diagram illustrating a state in which the stylus pen held by the holder of the device that reciprocates moves on the touch panel. is there.

(Stylus pen detection evaluation)
A tablet computer provided with a stylus pen of Reference Examples 1 to 9, Examples 10 to 15 and Comparative Examples 1 to 3, and a projection touch panel was prepared. Next, an electronic balance was prepared, and the display of the electronic balance was set to 0 with the tablet computer placed on the plate of the electronic balance. When the tablet computer is placed on the electronic balance, an icon that changes the screen of the touch panel is displayed when the stylus pen tip is brought into contact with the center of the touch panel. From the direction perpendicular to the touch panel, the pen tip of the stylus pens of Reference Examples 1 to 9, Examples 10 to 15 and Comparative Examples 1 to 3 is initially pressed with only the weight of the stylus pen, Thereafter, the pressing force was gradually increased, and the load indicated by the electronic balance when the icon reacted was confirmed.

Table 1 summarizes the evaluation results of the stylus pen.

It is a figure which shows stylus pen A (A1) of 1st Embodiment of this invention. It is a figure which shows stylus pen B (B1, B4) of 2nd Embodiment of this invention. It is a figure which shows the stylus pen C of the comparative example 1. FIG. It is a figure which shows the stylus pen D of the comparative example 2. FIG. It is a figure which shows the method of the ease evaluation of the touchscreen surface of a stylus pen.

A, B, C, D, E, A1-A9, B1-B6: Stylus pen

Claims (2)

A stylus pen for use in a capacitive touch panel, a silicone layer having a thickness of 30 to 150 μm on the surface of a metal pen tip that comes into contact with the touch panel and containing carbon nanotubes in a proportion of 2 wt% to 5 wt% A stylus pen characterized by providing The silicone rubber used in the silicone layer is obtained by curing a silicone composition comprising a diorganopolysiloxane having two or more alkenyl groups in one molecule and an organohydrogenpolysiloxane by an addition reaction. The organopolysiloxane is a linear diorganopolysiloxane having vinyl groups only at both ends, a linear diorganopolysiloxane having vinyl groups at both ends and side chains, and a branched diorgano having vinyl groups only at the ends. 2. The stylus pen according to claim 1, wherein the stylus pen is cross-linked with at least one silicone selected from polysiloxane and branched diorganopolysiloxane having vinyl groups at terminals and side chains as a main component.

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