JP2013254388A - Connection cable structure of four-wire type touch panel, and four-wire type touch panel including connection cable structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of fluctuation of contact resistance with a connector due to positional deviation or the like, in a connection cable structure of a four-wire type touch panel that includes eight-pin connector, and is connected with a coordinate detection circuit made to support both four-wire type and eight-wire type touch panels.SOLUTION: A connection cable structure of a four-wire type touch panel includes four wiring patterns 31' respectively connected to respective two pins of a connector. Two contact points P contacting the two pins of the respective wiring patterns 31' are integrated with each other in a width direction of the wiring patterns 31' without separation.

Description

  The present invention relates to a resistive film type touch panel, and more particularly to the structure of a connection cable for a 4-wire touch panel.

  Resistive touch panels include, for example, a 4-wire type and an 8-wire type depending on the detection method. 4A shows an outline of a 4-wire touch panel together with a coordinate detection circuit. The touch panel 10 includes a touch panel body 20 and a connection cable 30. FIG. A connector 50 into which the connection cable 30 is inserted and connected is mounted on the coordinate detection circuit 40.

  Although not shown in detail in FIG. 4A, the touch panel body 20 is configured by a lower substrate and an upper substrate that are arranged to face each other with a slight gap. Glass is generally used for the lower substrate, and a film is generally used for the upper substrate. A transparent resistance film is formed over the entire surface of the opposing surfaces of the lower substrate and the upper substrate. For example, on the resistance film of the upper substrate, as shown in FIG. 22 is formed, and electrodes 23 and 24 are formed on both ends of the Y-axis direction on the resistance film of the lower substrate.

  When detecting the X coordinate, the voltage Vcc is applied between the electrodes 21 and 22. At this time, when the upper substrate is touched and the coordinates (x1, y1) are pressed, the resistance film of the upper substrate and the resistance film of the lower substrate come into contact at the coordinates (x1, y1). Thereby, the potential Vx1 at the X coordinate x1 of the resistance film of the upper substrate is detected by the electrodes 23 and 24 through the resistance film of the lower substrate, and the X coordinate x1 is recognized by the detected potential Vx1.

  Similarly, the voltage Vcc is applied between the electrodes 23 and 24 when detecting the Y coordinate. At this time, when the upper substrate is touched and the coordinates (x1, y1) are pressed, the resistance film of the upper substrate and the resistance film of the lower substrate come into contact at the coordinates (x1, y1). Thereby, the potential Vy1 at the Y coordinate y1 of the resistance film of the lower substrate is detected by the electrodes 21 and 22 through the resistance film of the upper substrate, and the Y coordinate y1 is recognized by the detected potential Vy1.

  Thus, in the 4-wire touch panel, the electrodes 21, 22, 23, and 24 are used for both voltage application and detection, and voltage application and detection are switched by the switching circuit on the coordinate detection circuit 40 side. Yes.

  On the other hand, the 8-wire touch panel has a voltage application electrode and a detection electrode separately, and the 4-wire touch panel and the 8-wire touch panel are appropriately selected and used depending on the application. In the 4-wire touch panel, four wiring patterns are led out to the connection cable, and in the 8-wire touch panel, eight wiring patterns are led out to the connection cable.

  In Patent Document 1, although the electrodes at both ends in the X-axis direction and the electrodes at both ends in the Y-axis direction are commonly used for both voltage application and detection, the wiring pattern is removed in order to eliminate the influence of the resistance of the wiring pattern. A touch panel is described in which a wiring pattern is derived from both ends of each electrode and eight wiring patterns are derived to a connection cable so that the resistance value of each electrode can be detected.

JP 2005-284604 A

  As described above, the resistive touch panel includes a 4-wire type in which four wiring patterns are led out to the connection cable and an 8-wire type in which eight wiring patterns are led to the connection cable. .

  On the other hand, in the design of the coordinate detection circuit, consideration has been given so as to be compatible with both 4-wire type and 8-wire type touch panels for the purpose of sharing components. A coordinate detection circuit that can handle both equations is actually used.

  The coordinate detection circuit 40 shown in FIG. 4A is configured so as to be compatible with both 4-wire and 8-wire touch panels, and is also compatible with 8-wire touch panels. Therefore, the connector 50 has eight pins (contact pins).

  When the coordinate detection circuit 40 provided with such an 8-pin connector 50 and adapted to both a 4-wire type and an 8-wire type touch panel is used, the connection cable 30 of the 4-wire type touch panel 10 is conventionally known. Adopted the structure shown in FIG. 4B. That is, the tip portion of each wiring pattern 31 inserted and connected to the connector 50 is divided into two parts to form a bifurcated shape. This is the same wiring pattern shape that contacts each pin of the 8-pin connector 50 as that of the 8-wire wiring pattern. That is, the 4-wire touch panel is an 8-wire touch panel when viewed from the coordinate detection circuit 40 side. It can be used as a pin compatible.

  A total of eight connecting portions 32 at the tips of the four wiring patterns 31 are brought into contact with each other and one pin of the connector 50 is brought into conduction. As shown in FIG. 4C, the connector 50 has an opening 51 into which the tip of the connection cable 30 is inserted, and eight pins 52 are arranged in the opening 51. A contact portion 52a is formed to bend and project at the tip end side of the pin 52.

  On the other hand, the connection cable for the touch panel has been conventionally manufactured using FPC, but in order to reduce the cost, a wiring pattern formed by printing instead of FPC has been used. In this case, the wiring pattern is generally formed by overprinting Ag paste and carbon. Carbon is printed so as to cover the printed part of the Ag paste to prevent oxidation of Ag.

  When a wiring pattern is formed by overprinting Ag paste and carbon in this way, the contact resistance between the pin and the wiring pattern connection portion is reduced due to the printing displacement of the Ag paste and carbon and the positional deviation between the connector pin and the wiring pattern. As a result, there is a problem that the touch position of the touch panel cannot be detected correctly, resulting in misalignment.

  5A and 5B show a state in which the contact resistance changes due to such printing misalignment or positional misalignment between the pin and the wiring pattern connecting portion, and a part of the connecting portion 32 of the wiring pattern 31 shown in FIG. This is shown in contrast to the case. 6A and 6B are enlarged views of the CC cross section of FIG. 5A and the DD cross section of FIG. 5B, respectively.

  6A and 6B, reference numeral 33 denotes a base material of the connection cable 30. As shown in FIG. 6A, the Ag paste 34 is printed on the base material 33, and the carbon 35 is overprinted on the Ag paste 34. The carbon 35 is printed large (wide) in consideration of printing misalignment. For the base material 33, PET or the like is used. In the connection cable 30 shown in FIG. 4B, the arrangement pitch of the eight (8) connection portions 32 is, for example, 1.25 mm. In this case, the width W1 of the Ag paste 34 in the connection portion 32 is, for example, 0. The width W2 of the carbon 35 is, for example, 0.8 mm. The film thicknesses of the Ag paste 34 and the carbon 35 are each about 10 μm.

  FIG. 5A shows a case where there is no printing misalignment between the Ag paste 34 and the carbon 35, and FIG. 5B shows a case where there is a large printing misalignment. 5A and 5B, the black circle P indicates the position of the contact point that contacts the pin 52 of the connector 50 in the connection portion 32, and in FIGS. 6A and 6B, the arrow Q indicates the direction and position where the contact portion 52a of the pin 52 contacts. Indicates.

  In FIG. 5A, the two pins 52 are in contact with the portion where the Ag paste 34 and the carbon 35 overlap each other with respect to the two connection portions 32 of the single wiring pattern 31, and the contact P is positioned at the correct position. . On the other hand, if the printing of the Ag paste 34 and the carbon 35 is shifted and the pin 52 and the connecting portion 32 are displaced, the contact P is located at the position shown in FIG. 5B. In this case, the contact P in each connection portion 32 is not the correct position where the Ag paste 34 and the carbon 35 overlap, but is located only in the carbon 35, that is, between the two pins 52 of one wiring pattern 31. Both of the contacts P are located only in the carbon 35, and therefore the contact resistance between the pin 52 and the wiring pattern 31 is increased.

  On the other hand, it cannot be said that the position of the contact P is maintained constant. For example, since the position can be changed by external force or vibration applied to the connection cable or the like, when external force or vibration is applied when the touch panel is used, FIG. When there is a print misalignment between the Ag paste 34 and the carbon 35, the contact resistance between the pin 52 of the connector 50 and the wiring pattern 31 is likely to fluctuate, thereby correctly detecting the touch position of the touch panel. It is possible to cause a situation in which the position shift occurs.

  In view of such a problem, an object of the present invention is to provide a connection cable structure for a four-wire touch panel that is unlikely to cause a situation in which the contact resistance with the connector fluctuates, and thus is less likely to cause displacement in touch position detection. Another object of the present invention is to provide a four-wire touch panel having the connection cable structure.

  According to the first aspect of the present invention, the connection cable for the 4-wire touch panel that is connected to the coordinate detection circuit that is provided with an 8-pin connector and is compatible with both 4-wire and 8-wire touch panels is a connector. Structure having four wiring patterns connected to each of the two pins, and the two contact points contacting the two pins in each wiring pattern being integrated without being separated in the width direction of the wiring pattern It is supposed to have.

  In the invention of claim 2, in the invention of claim 1, the wiring pattern is made of Ag paste printed on the base material and carbon printed on the Ag paste.

  According to the invention of claim 3, the four-wire touch panel is provided with the connection cable structure of claim 1 or 2.

  According to the present invention, for example, even if a positional deviation occurs between the connection cable and the connector, one of the two pins of the connector always comes into contact with the correct position of the wiring pattern. Therefore, it is difficult to cause a situation in which the contact resistance of the connector pin fluctuates. Therefore, it is possible to solve the problem that the displacement of the touch position detection occurs due to the fluctuation of the contact resistance.

The top view which shows one Example of the connection cable structure by this invention. The figure which shows the contact position of a wiring pattern, A is a case where there is no printing misalignment of Ag paste and carbon, B is a case where there is a printing misalignment of Ag paste and carbon. The figure for demonstrating the other Example of the connection cable structure by this invention. A is a plan view showing an outline of a state where a 4-wire touch panel and a coordinate detection circuit are connected, B is a plan view showing a conventional structure of a connection cable in A, and C is a cross-sectional view of a connector in A. FIG. The figure which shows the contact position of the conventional wiring pattern, A is a case where there is no printing misalignment of Ag paste and carbon, B is a case where there is a printing misalignment of Ag paste and carbon. 5A is a CC cross-sectional view of FIG. 5A, and B is a DD cross-sectional view of FIG. 5B.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows an embodiment of a connection cable structure of a four-wire touch panel according to the present invention. A connection cable 30 ′ has four wiring patterns 31 ′, and connectors 50 of the respective wiring patterns 31 ′. It is assumed that the front end inserted and connected (see FIG. 4A) is not provided with a bifurcated shape like the conventional wiring pattern 31 shown in FIG. 4B.

  FIG. 2 shows the position of the contact P at which the pin 52 of the connector 50 contacts when the wiring pattern 31 ′ is formed by overprinting Ag paste 34 and carbon 35, and the connection cable 30 ′ is connected. The coordinate detection circuit 40 (see FIG. 4A) is configured to be compatible with both 4-wire and 8-wire touch panels, and the connector 50 has eight pins. Therefore, two contact points P are located on each wiring pattern 31 ′.

  FIG. 2A shows a case where there is no print misalignment between the Ag paste 34 and the carbon 35, and FIG. 2B shows a case where there is a large print misalignment. In FIG. 2A, the two contact points P with respect to one wiring pattern 31 'are both positioned at the correct positions where the Ag paste 34 and the carbon 35 overlap. On the other hand, even if there is a printing misalignment as shown in FIG. 2B, one of the two contacts P is located at the correct position where the Ag paste 34 and the carbon 35 overlap as shown in FIG. According to this example, the situation in which the contact resistance between the wiring pattern 31 ′ and the pin 52 of the connector 50 increases occurs even if there is a printing misalignment between the Ag paste 34 and the carbon 35 or a positional misalignment between the pin 52 and the wiring pattern 31 ′. It will be difficult.

  This is the same as the structure of the conventional connection cable 30 shown in FIG. 4B in that there are two contact points P that contact the two pins 52 in one wiring pattern 31 ′. This is because the contact P is integrated without being separated in the width direction of the wiring pattern 31 ′.

If such a structure of the connection cable 30 ′ is employed, the following effects and advantages can be obtained.
a) Since the situation that the contact resistance fluctuates due to the displacement of the contact P due to external force or vibration is less likely to occur than before, the problem of the displacement of the touch position detection of the touch panel due to the variation of the contact resistance is solved. can do.
b) The fitting accuracy with the connector can be relaxed as compared with the conventional case.
c) In general, the connecting cable is covered with an insulating film on the wiring pattern except for the connecting portion with the connector, which makes it difficult to visually check the wiring pattern. In this case, since the eight connection portions 32 are visible at the tip of the conventional connection cable 30, it is impossible to distinguish from the eight-wire type only by this portion, but the four connection patterns 31 of the connection cable 30 ′ of the present invention are not possible. Because 'is visible, it can be easily distinguished from the 8-wire type.

  In addition, as shown in FIG. 3, in printing the Ag paste 34, a notch 34 'may be provided at the tip to form a bifurcated shape. The depth (length) of the notch 34 ′ is set so as not to reach the position of the contact P.

DESCRIPTION OF SYMBOLS 10 Touch panel 20 Touch panel main body 21-24 Electrode 30, 30 'Connection cable 31, 31', 31 '' Wiring pattern 32 Connection part 33 Base material 34 Ag paste 34 'Notch 35 Carbon 40 Coordinate detection circuit 50 Connector 51 Opening part 52 Pin 52a Contact part

Claims (3)

A structure of a connection cable of a 4-wire touch panel that is connected to a coordinate detection circuit that is provided with an 8-pin connector and can be adapted to both 4-wire and 8-wire touch panels,
There are four wiring patterns respectively connected to each of the two pins of the connector, and the two contacts that contact the two pins in each of the wiring patterns are integrated without being separated in the width direction of the wiring pattern. A connection cable structure for a four-wire touch panel. In the connection cable structure of the 4-wire type touch panel according to claim 1,
4. The connection cable structure for a 4-wire touch panel, wherein the wiring pattern is made of Ag paste printed on a base material and carbon printed on the Ag paste.   A four-wire type touch panel comprising the connection cable structure according to claim 1.

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