KR20200106237A - touch panel for vehicle using conductive polymer - Google Patents

Abstract

Disclosed is a vehicle touch panel in which all touch patterns in a touch area are connected to a control board on a transparent substrate constituting a touch pad through a connection pattern with excellent conductivity compared to touch patterns, and the touch patterns are in electrical connection with connection patterns through a plurality of points to increase the stability of signal transmission between the touch patterns and the connection patterns. In order to connect a plurality of points of the touch patterns and the connection patterns, one or more auxiliary connection patterns branched from the connection patterns in an area outside the touch patterns can be provided, and an edge line surrounding the touch patterns while overlapping the touch patterns can be formed in the periphery of the touch patterns as connection reinforcement patterns having excellent conductivity compared to the touch patterns for improving the stability of signal transmission between the touch patterns and the connection patterns. According to the present invention, electrical connection between the touch patterns and the connection patterns is established in other parts of the touch patterns even when cracks occur in a connection part between touch patterns with relatively low conductivity and touch patterns with relative high conductivity of the vehicle touch panel or the peripheral thereof, thereby transmitting touch signals to a control board properly through the same.

Description

Touch panel for vehicle using conductive polymer

The present invention relates to a touch panel for a vehicle, and more particularly, a touch region is formed using a conductive polymer to enhance the conductivity stability between the touch region and a conductive pattern (connection pattern) for connection in a touch panel installed on a vehicle dashboard. It relates to a touch panel for a vehicle having a configuration that can be made.

In recent years, a display device and a touch pad are combined, and a touch panel or a touch screen panel (TSP) made to implement a function assigned to a corresponding area on the display by touching a partial area of the display screen by cooperating with them through a control device such as a control board. ) Is often used.

Such a touch panel can be used in various ways as a control and input means serving as a display device for a mobile phone, a tablet computer, a notebook computer, and various equipment, and the use of the touch panel is rapidly increasing as the use of smart phones increases.

The touch pad used in such a touch panel allows the user to select and realize desired functions by immediately touching an object displayed on the display. Therefore, it is integrated with the display so that there is no need to have an input means such as a separate keyboard. Portability can also be improved.

Touch pads have been developed with various methods and structures and are well known in detail. For example, capacitive touch pads are particularly classified in several ways, and their structures are well known and used most. Resistive touch pads are also known from the beginning for their merit such as enabling precise touch. Since various configurations and methods of such a touch pad are already well known in the art and most have been established, a description of each specific configuration will be omitted here.

Such a touch pad is installed and used in a center fascia or an instrument panel for vehicles. Here, too, the touch pad forms a touch pattern with a conductive film in a specific area of the substrate, and when the portion is touched, a signal is transmitted to the control board outside the touch panel along a connection wire. For this purpose, a part of the connecting lead is normally overlapped at the periphery of the pattern, and the ends of the connecting lead overlapping with the pattern are expanded to form an electrical terminal or a connection so that signal current is efficiently transmitted.

The touch pad must be transparent so that the user can see and touch the screen of the display coupled thereto in the touch panel, and in the most commonly used capacitive or resistive touch pad, a conductive layer or a The conductive pattern becomes essential.

In order to connect the touch pattern made of conductive polymer in the touch area to the control board, a connection wire pattern or connection pattern that connects a considerable distance is required. When this connection pattern is made of a conductive polymer, transparency is good, but conductivity is weakened, causing problems. I can. Therefore, the connection pattern can be made of a metal paste having better conductivity than the touch pattern.

Therefore, referring to the cross-sectional view of FIG. 1 and the plan view of FIG. 2, the display screen is visible through the touch pad when the conductive layer or the touch pattern 13 of the touch area is formed on the substrate 11 forming the touch pad. A transparent conductor is used, and ITO (indium tin oxide), a kind of a metal oxide conductor, is most widely used as a transparent conductor. In FIG. 1, reference numeral 13 denotes a touch pattern, reference numeral 15 denotes a silver paste layer connection pattern used to increase conductivity when connecting the touch pattern of the touch area and the connection (connection for connection with the control board), and 17 Denotes an overcoat film for protecting these conductive patterns, and reference numeral 19 denotes an OCA layer used to attach another substrate layer or window thereon.

Below the substrate forming such a touch pad, there is a display device (not shown) that is usually coupled to form a touch panel, and at the connection portion of the touch pad, a conductive pattern corresponding to the terminal is flexible through an anisotropic conductive film (ACF:20). It is combined with the conductive layer 31 of the printed circuit board (FPCB: 30). The conductive layer 31 exposed to the other end of the flexible printed circuit board is connected to the terminal pattern 45 exposed on the surface of the substrate 41 of the control board 40 in various ways, so that the touch pad and the control board are electrically connected. To be connected.

However, ITO is usually made through a vacuum thin film process such as sputtering deposition, and in order to form a pattern, it is necessary to undergo a photolithography process, and if the substrate is required to be bent, it is difficult to maintain a durable adhesion state to the substrate. there is a problem.

On the other hand, as the frequency of use and use of touch panels increases, the need to be applied to flexible displays is increasing, and when commercialization is made, the pressure to reduce manufacturing costs is constantly applied, such as vacuum lamination processes such as ITO lamination and patterning, or photolithography. Since the process is a process that requires a lot of equipment and process costs, there is a problem that cost reduction is not easy.

Rather than depositing an ITO film as a transparent conductive film in a vacuum environment and patterning it through photolithography, many development studies have been conducted to form and use a PEDOT-based polymer transparent conductive pattern in a direct printing form. However, since the PEDOT film is difficult to control viscosity, inkjet printing is not suitable, it is not easy to form a fine pattern due to its high flowing property, and a short circuit between adjacent patterns may occur.

A silver paste conductive pattern is sometimes used to form a long conductive line pattern or a connection pattern of a panel. Silver paste has good conductivity, but the transparency decreases rapidly as it gets thicker. Therefore, it is difficult to make a transparent conductive pattern with only silver paste. In many cases, the transparency is formed in a printing form on a part where it is not a problem and is used for a limited amount.

On the other hand, the vehicle dashboard is mainly composed of an instrument panel, a center fascia, and a console box. In the instrument panel and center fascia, a display screen and buttons for controlling vehicle elements are intensively installed. Conventionally, the display screen and the control button are often composed of separate configurations, and the control button has been mainly composed of a mechanical configuration such as a push button, but in recent years, the electronic elements of the vehicle are strengthened and the user's convenience is emphasized, so that the display object and the button The introduction of touch panel methods that can be intuitively integrated is increasing.

In conventional automotive touch panels, a silver paste conductive pattern (connection pattern: 15) is formed together with a transparent conductive pattern (touch pattern: 13) in the touch area, so that even if some loss of transparency is lost, stability in signal transmission is often achieved. , The connection pattern 15 made of silver paste is inserted into the connection part 15a of the touch pattern 13 of the touch area as shown in the partially enlarged view of FIG. 2, and the connection part 15a in which the touch pattern and the connection pattern are connected. ), the end is branched or enlarged in a T-shape to widen the boundary line where the touch pattern 13 meets the connection pattern 15.

Since this extended boundary is used for signal inflow or charge inflow from the touch pattern 13 to the connection pattern 15, there is generally no problem in signal transmission from the touch pattern to the silver paste connection pattern, but the touch pattern and seamless electricity When a crack (crack: 300) occurs at the connection part as shown in the partially enlarged view of FIG. 2 for some reason at the place where the expanded silver paste connection pattern (connection line) for connection meets each other, the dotted line arrow in FIG. As shown, the touch pattern 13 is transferred to the silver paste connection pattern 15 only through a very narrow connection of the connection part.

That is, the electric charge caused to the touch pattern by the touch of the touch area can be transmitted to the connection pattern only through a narrow width in which the crack 300 does not occur, which is likely to be a very small amount compared to the case where the crack does not occur. As a result, since the signal strength of the touch signal is weak, it is difficult to properly transmit the touch signal to the control board, an error in recognition may occur, and there is a problem in that a function is not implemented by a touch.

Such cracks can be made by being damaged laterally even in the state of a finished product, and because of the nature of the touch panel material, they are often folded or bent, and cracks may occur in the pattern during such a process. In addition, even in the process of making the silver paste connection pattern, such cracks or cracks may occur due to a process error.

Therefore, it would be desirable if there is a configuration or method capable of more reliably transmitting the signal of the touch area to the silver paste connection pattern in order to prevent the defect of the touch panel due to this problem.

WO 2012015254A2: Method for manufacturing a transparent conductive film and a transparent conductive film manufactured by means Republic of Korea Patent Publication No. 10-2014-0125932: Printed layer integrated touch screen panel Republic of Korea Patent Registration No. 10-1617784: Touch screen type automobile center face panel and manufacturing method of the center fascia panel Republic of Korea Patent Registration No. 10-1648029: Touch screen display device, a vehicle with a touch screen VYTLW device, and a method of controlling a touch screen display device Republic of Korea Patent Laid-Open Patent No. 10-2013-0069076: Connection structure of touch panel substrate and FPCB

An object of the present invention is to provide a structure for solving a problem in which a touch signal is not properly transmitted when a connection pattern of a conventional vehicle touch panel and a touch pattern are connected to each other or a crack occurs around the connection portion.

An object of the present invention is to provide a touch panel for a vehicle having a structure capable of sufficiently transmitting a signal in a touch area even when a part of a crack occurs without particularly increasing the burden on the process.

In order to achieve the above object, the touch panel for a vehicle of the present invention is characterized in that a touch pattern of a touch area is electrically connected to a connection pattern through a plurality of locations on a transparent substrate constituting a touch pad.

In the present invention, a plurality of connection patterns electrically connected to one touch pattern are formed to connect a plurality of locations and a connection pattern, or an auxiliary connection pattern branched from an area outside the touch pattern to connect one connection pattern and a plurality of locations is provided. It may be further provided. In this case, when a plurality of connection patterns are formed, they can be combined into one at the connection part with the control board, and the auxiliary connection pattern can be widely viewed as a connection pattern.

In the present invention, a connection pad in which the connection pattern is enlarged using the same material as the connection pattern may be installed at a portion where the connection pattern and the touch pattern are connected.

In the present invention, an edge line surrounding the touch pattern may be formed at the periphery of the touch pattern as a connection reinforcing pattern for improving the stability of signal transmission between the touch pattern and the connection pattern, which is superior to the touch pattern.

In the present invention, the touch pattern of the touch panel is made of a conductive polymer, such as a PEDOT-based material, and the connection pattern and the border line (connection reinforcement pattern) are each formed of a material having superior conductivity compared to the conductive polymer, such as silver paste or other metal paste. Can be.

In the present invention, the touch pattern made of a conductive polymer, the border line, and the connection line may all be formed by a printing method, and it is preferable that the border line and the connection pattern are integrally formed simultaneously with the same material.

According to the present invention, electrical connection between the touch pattern and the connection pattern is made at other places of the touch pattern even when a crack occurs in or around the connection between the relatively low conductivity touch pattern and the relatively high conductivity connection pattern of the vehicle touch panel. Through the part, the touch signal can be properly transmitted to the control board through the connection pattern.

According to the present invention, a signal can be sufficiently transmitted even when a partial crack occurs in a connection portion to which the connection pattern and the touch pattern are connected, without particularly increasing the burden on the process.

1 is a cross-sectional view showing a touch pattern of a conventional touch pad, a layer structure of a connection pattern, an anisotropic conductive film connected thereto, and an FPCB configuration;
2 is a plan view showing a schematic configuration of a conventional touch pad, and a partially enlarged view showing a connection portion between a touch pattern and a connection pattern and cracks (cracks) generated therein;
3 is a conceptual diagram for explaining a problem of signal transmission in a situation such as the enlarged view of FIG. 2;
4 is a plan view showing an embodiment of a touch pad that can be used in the touch panel of the present invention;
FIG. 5 is a plan view showing the advantages of signal transmission due to cracks generated at the connection portion or around the touch pattern, the edge line, and the electrical connection pattern in the touch pad constituting another embodiment of the present invention;
6 is a plan view for explaining that there is no significant influence between electrical connections and signals even if there is an alignment error when overlapping border lines and connection patterns by printing while a touch pattern is formed on the touch panel substrate of the present invention.

Hereinafter, the present invention will be described in more detail through specific examples with reference to the drawings.

FIG. 4 is a plan view illustrating an instrument panel-shaped substrate forming a touch pad of a touch panel for a vehicle according to an embodiment of the present invention, and conductive patterns stacked on the substrate.

The overall configuration is similar to the conventional touch pad configuration as shown in FIG. 2. Here, the substrate 11 is a substrate made of a flexible film that can be easily bent or bent, and made of a tough and durable polyethylene terephthalate (PET) material to form the base of the touch pad. In addition to PET as a substrate material, polycarbonate (PC: polycarbonate), which has excellent light resistance, heat resistance, impact strength, and insulation, has excellent low specific gravity and abrasion resistance, polypropylene (PP), which has excellent chemical resistance and water resistance. Polyethylene), a variety of materials such as acrylonitrile butadiene styrene (ABS) having excellent hardness, chemical resistance, heat resistance, gloss, insulation and ductility can be used.

The shape of the substrate can also be cut into any shape. Here, since the board itself is flexible, even if a separate flexible printed circuit board (FPCB) is not intervened between the board and the control board, when mounted on the dashboard, part of the touch pad extends long from the part covering the display screen similar to the FPCB. It is formed to have 200 and is also partially bent, so that it can be easily directly connected to a control board built in another spaced apart.

Although not shown here, a connection portion having a plurality of connection terminals is provided at the end of the elongated extension portion 200 of the substrate to be connected to the control board similar to that shown in a conventional touch panel.

A conductive pattern is installed on the surface of the substrate 11 constituting the touch pad in a printing method. As a conductive pattern, a touch pattern of a touch area and a connection pattern for electrical connection between a control board connection terminal and the touch pattern are formed. However, in this case, the auxiliary connection pattern 117 branched from the connection pattern 115 outside the touch pattern area is connected to the connection portions 115a of the touch pattern 113 spaced apart from each other, unlike the conventional one. In a portion where the touch pattern 113 and the auxiliary connection pattern 117 are connected to each other at the connection portion 115a, there is a connection pad 117a formed by expanding the end of the auxiliary connection pattern 117.

Here, the touch pattern 113 is made of a PEDOT layer, and the connection pattern 115, the auxiliary connection pattern 117, and the connection pad 117a are simultaneously integrated by a printing method and are made of a silver paste layer.

PEDOT represents poly_3,4_ethylenedioxythiophene, and is commonly used in the form of a polymer mixture of two ionomers called PEDOT:PSS (poly(3,4-ethylenedioxythiophene) polystyrene sulfonate). PEDOT is a kind of conductive polymer, and it can be made into a liquid form such as ink to easily implement a conductive pattern through a printing method. This conductive pattern has the advantage of being light, strong, bendable, and high in chemical durability.

Since the ink for forming the PEDOT layer touch pattern 113 is usually low in viscosity, there is a concern that a short circuit may occur between the PEDOT layer touch patterns 113 due to spreading during printing, and a thickness deviation of the printing area may occur. have. Therefore, it is preferable to perform corona treatment or plasma treatment on the PET substrate 11 in order to realize a clear touch area and uniform touch sensitivity, or to install a coating film to reduce surface tension due to the material characteristics of the substrate surface. In addition, it is desirable to use the printing equipment itself as a high-spec printing equipment in order to increase the clarity of printing so that not only the spread but also the thickness can be managed.

In this embodiment, even when a crack 300 is formed in some of the connection portions 115a, the auxiliary connection pattern 117 and the connection pattern 115 are connected from the connection pads 117a of the other connection portions 115a. The electric signal when the touch pattern is pressed can be transmitted to the control board in a sufficient size.

FIG. 5 is an enlarged view of one touch pattern portion in an embodiment in which a border line is further formed differently from the embodiment of FIG. 4.

Here, when forming the connection pattern, the auxiliary connection pattern, and the connection pad, a connection reinforcement pattern or an edge line surrounding the touch pattern while overlapping with the periphery of the touch pattern is also formed. The connection pattern 115, the auxiliary connection pattern 117, the connection pad 117a, and the border line 119 are formed integrally at the same time by a printing method and are formed of a silver paste layer.

Here, the border line 119 is formed to surround the touch area while overlapping the edge of the substantially circular touch pattern 113. The auxiliary connection pattern 117 is enlarged while one end is connected to the edge line 119 to form a connection pad 117a, and the other end is connected to the connection pattern 115. The silver paste layer forming them is made in the form of ink with silver nanowires and is also installed in a printing method. The silver paste layer pattern may also play a role of reducing noise due to surrounding structures through GND shielding printing.

Compared with the conventional Fig. 3, in the case of the illustrated crack 300, in Fig. 3, the T-shaped end of the silver paste connection pattern overlaps only at one periphery of the touch pattern of the touch area, and charges, that is, signals are transmitted only through this part. The stability of signal transmission can be an issue. In FIG. 5, the connection pad 117a at the end of the auxiliary connection pattern 117 and the rim line 119 are connected, and the rim line surrounds the entire periphery of the touch pattern and forms a circumferential shape overlapping the entire periphery. Since silver paste has a very high conductivity compared to the PEDOT conductive polymer, the auxiliary connection pattern 117 connects the connection pad 117a even when the crack 300 as shown in FIG. 3 is generated in the touch pad due to external factors. If it is connected to only one part of the edge line 119 through the connected part, electric charges generated through the entire touch area may be transmitted through the connected part, and the problem of signal strength decrease due to cracking is not important.

In addition, since the connection part is installed in multiple places of the touch pattern, and each connection part is connected to the auxiliary connection pattern, when a touch is made to the touch area, the electric charge induced in the part flows around in various directions and reaches the silver paste border line. And, even if there is a crack in the middle of the border line, charges or signals are focused using the border line as a connection pad 117a and an auxiliary connection pattern at the connection part connected to the border line, like a highway, and flows in the auxiliary connection pattern and connection pattern. .

Of course, the signal flowing through the connection pattern is transmitted to the connection terminal at the other end of the connection pattern, and through this, it is transmitted to the control board outside the touch panel, so that a function corresponding to the touched area acts.

Here, a silver paste is used as an edge line for the connection pattern and the touch pattern of the touch area, but a pattern having good conductivity of a material other than the silver paste may be used, and there is no need to be limited to silver paste.

6 is a big problem in performing a function by touch even when there is an alignment error in the printing step where the touch pattern 113 of the touch area, the silver paste border line 119, and the auxiliary connection pattern 117 do not completely overlap at the exact position. This is a conceptual diagram to explain the absence of

When the panel is tilted in the printing step and a slight rotational shift occurs based on the center of the touch pattern 113 at the original position, or the touch pattern 113 is slightly moved at the original position due to the parallel movement of the pad. In some of the connection parts at a plurality of locations, overlapping between the touch pattern, the connection pad, and the border line is sufficiently achieved, and the touch signal or signal current due to the touch operation sufficiently flows through the auxiliary connection pattern 117 and the connection pattern 15. , The signal strength is very limited, and there is no significant change in the actual signal strength, so that the function can be implemented normally by touch.

As a result, as shown in FIG. 6, in order to collect signals from the touch pattern 113 made of PEDOT conductive polymer, the panel and the printing device are Even if there is some mismatch in alignment, there is no big problem, and the problem of process defect does not occur.

In the above, the present invention has been described based on an embodiment having a circular touch pattern and a cylindrical border line, but the advantages of the present invention may be applied to other types of touch patterns and border lines in the same manner.

In the above, the present invention has been described through limited embodiments, but this has been illustratively described to aid understanding of the present invention, and the present invention is not limited to these specific embodiments.

Therefore, those of ordinary skill in the field to which the present invention belongs may implement various changes or application examples based on the present invention, and it is natural that such modifications or application examples belong to the appended claims.

11: substrate 13, 113: touch pattern
15, 115: connection pattern 115a: connection
117: auxiliary connection pattern 117a: connection pad
119: border line 200: extension
300: crack (crack)

Claims (4)

A touch panel for a vehicle having a transparent touch pattern on a transparent substrate, a touch pad having an electrical terminal of a connection part for transmitting a signal induced by the touch pattern to the outside, a connection pattern for transmitting a signal subsequent to the touch pattern and the electrical terminal In,
The transparent touch pattern is made of a conductive polymer,
The connection pattern is made of a material having superior conductivity compared to the touch pattern,
The touch panel for a vehicle, wherein the touch pattern makes electrical connection with the connection pattern at a plurality of locations. The method of claim 1,
A touch panel for a vehicle, comprising a material having superior conductivity compared to the touch pattern, and further comprising an edge line surrounding the touch pattern so as to overlap the periphery of the touch pattern, and wherein the connection pattern is electrically connected to the edge line. The method according to claim 1 or 2,
The touch pattern is made of a PEDOT-based material,
The connection pattern is formed of a metal paste,
The edge line is a touch panel for a vehicle, characterized in that formed by a printing method at the same time made of the same material as the connection pattern. The method according to claim 1 or 2,
In the plurality of locations, a plurality of connection patterns electrically connected to one touch pattern are formed to connect the touch pattern and the connection pattern, or in an area outside the touch pattern to connect one connection pattern and the plurality of locations. A touch panel for a vehicle, wherein at least one auxiliary connection pattern branched from the connection pattern is further provided.

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