JP2010244357A - Touch panel of capacitance detection type - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a touch panel of a capacitance detection type which detects high-precision coordinate by eliminating a difference in parasitic capacitance between electrodes. <P>SOLUTION: The touch panel of the capacitance detection type includes a plurality of detection electrodes 6, 7 formed and arranged in lines on one side of a transparent base 1, the detection electrodes having the same shape on the same axes as an X-axis direction and a Y-axis direction which are mutually perpendicular. The line lengths of the detection electrodes 6, 7 are different between the X-axis direction and the Y-axis direction, and the area of the detection electrode (each of the detection electrodes 7 forming a Y-wiring pattern 3) in a direction in which their alignment length is long is smaller than the area of the detection electrode (each of the detection electrodes 6 forming an X-wiring pattern 2) in a direction in which the alignment length is short. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a capacitance detection type touch panel that detects a change in capacitance caused by touching a finger and detects position information of a position touched by the finger.

  In recent years, electronic devices such as computers have more and more equipped with a coordinate input device that detects coordinates by detecting a change in capacitance. For example, information can be easily input by touching a touch panel with a finger or the like. And can be operated.

  A coordinate input device that detects a change in capacitance uses, for example, the fact that the distance between the electrodes changes by pressing two opposing electrodes, and the capacitance changes accordingly. It is also known to detect and analyze an input from a user, and further to detect using an electrostatic capacitance (capacitor) change caused by a finger touch. For example, a method of detecting touch coordinates by applying a voltage of the same potential to four corners of one electrode and converting the formation of capacitance (capacitor) by finger touch to weak current change flowing through the four corners. Has been proposed, and coordinates can be input by simply touching a finger.

  However, in the method of detecting coordinates by touching one electrode with the finger, it is difficult to determine the coordinates when touching a plurality of locations simultaneously. Therefore, we propose a method that allows multiple points to be input by arranging multiple electrodes that detect capacitance changes in XY coordinates and detecting the capacitance change point by touching the finger with absolute coordinates. (See, for example, Patent Document 1).

  The sensor described in Patent Document 1 is a capacitive sensor for determining the position of an object along a first direction and a second direction. As the configuration, first, a substrate is provided in which electrodes are arranged on one surface. The electrodes are arranged to define an array of detection cells arranged in columns and rows for forming detection regions. Each of the detection cells includes a column detection electrode and a row detection electrode, the column detection electrodes of the detection cells in the same column are electrically connected to each other, and the row detection electrodes of the detection cells in the same row are also electrically connected to each other Yes. The row detection electrodes of the detection cells at at least one end of the row are connected to each other by an electrical connection made outside the detection region, so there is no need for the electrical connection to traverse the detection region, only on one side of the substrate. A capacitive position sensor having a detection region with an electrode can be realized.

JP 2007-18515 A

  By the way, the detection of the capacitance change due to the touch of the finger has a very small amount of change of several pF. For example, when a liquid crystal display device (LCD) or the like serving as a noise source is arranged around the change, the influence is exerted. May cause malfunction when detecting the amount of change in capacitance.

  As a countermeasure against such a malfunction, it is generated by arranging a conductive film or a conductor having the same effect on the surface opposite to the electrode forming surface of the substrate and setting the potential to ground (GND). A method of blocking noise can be considered.

  However, in particular, in the type of touch sensor in which several electrodes are arranged in the XY coordinates, malfunctions cannot be eliminated. In the type of touch sensor in which several electrodes are arranged on the XY coordinates, it is necessary to detect capacitance changes independently for each electrode, and it is necessary to make the respective parasitic capacitances equal within the range of the detection circuit. . At this time, if there is a conductor on the opposite side of the electrode, the parasitic capacitance further increases, and each electrode size (area of the entire electrode) in the XY coordinates depends on the vertical and horizontal dimensions, such as a touch panel having different vertical and horizontal dimensions. If they are different, there arises a problem that the parasitic capacitance difference between the electrodes becomes large. This phenomenon becomes more prominent when a thin substrate is used, for example, in order to realize high light transmittance.

  The present invention has been proposed for the purpose of solving the above-described conventional problems, and it is possible to realize a parasitic capacitance without variation for each electrode, and to enable static coordinate detection with high accuracy. An object is to provide a capacitance detection touch panel.

  In order to solve the above-described problem, a capacitive touch panel according to the present invention has a plurality of identical shapes on one surface of a transparent substrate that are coaxial in the X-axis direction and the Y-axis direction orthogonal to each other. A capacitance detection type touch panel having a wiring pattern in which detection electrodes are arranged in a line, wherein the line length of the detection electrode is different in the X-axis direction and the Y-axis direction. The area of each detection electrode in the long direction is smaller than the area of each detection electrode in the direction where the line length is short.

  For example, in capacitive detection type touch panels with different vertical and horizontal dimensions, the line lengths of the detection electrodes arranged in the X-axis direction are different from the line lengths of the detection electrodes arranged in the Y-axis direction. In this case, if the area of each detection electrode arranged in the X-axis direction is the same as the area of each detection electrode arranged in the Y-axis direction, X wiring (line arrangement in the X-axis direction, Y-axis direction) And the Y wiring (line arrangement in the Y-axis direction and the detection electrodes arranged in the X-axis direction) are connected to each other. The total area of the wiring is different, and the parasitic capacitance generated by touching with a finger is different.

  On the other hand, in the capacitance detection touch panel of the present invention, the area of each detection electrode in the long line length direction is smaller than the area of each detection electrode in the short line length direction. Thereby, the area difference of the whole wiring of X wiring (for example, wiring with short line length) and Y wiring (wiring with long line length) is suppressed, and a parasitic capacitance difference is reduced.

  According to the present invention, even when the lengths of the X wiring and the Y wiring are different, such as a touch panel having different vertical and horizontal dimensions, it is possible to realize a parasitic capacitance without variation for each wiring, and to provide highly accurate coordinates. It is possible to realize a capacitance detection touch panel capable of detection.

It is a schematic sectional drawing which shows an example of a capacitive detection type touch panel. It is a schematic plan view which shows an example of the conventional pattern of the electrode for a detection. (A) is a schematic plan view which shows the conventional X wiring pattern, (b) is a schematic plan view which shows the conventional Y wiring pattern. It is a schematic plan view which shows the example of a pattern of the electrode for a detection of embodiment. (A) is a schematic plan view which shows the X wiring pattern of embodiment, (b) is a schematic plan view which shows the Y wiring pattern of embodiment. It is a schematic plan view which expands and shows each detection electrode vicinity. It is a schematic plan view which shows the other example of a shape of the electrode for a detection.

  Hereinafter, embodiments of a capacitance detection type touch panel to which the present invention is applied will be described in detail with reference to the drawings.

  For example, as shown in FIG. 1, an electrostatic capacitance detection type touch panel has an X wiring (in the X-axis direction (for example, lateral direction) arranged in a line on one surface of a transparent substrate 1 made of glass, plastic film, or the like. X electrode) pattern 2 is formed, and Y wiring (Y electrode) pattern 3 arranged in a line in the Y-axis direction (for example, the vertical direction) is formed thereon via insulating layer 4. . Each of the X wiring pattern 2 and the Y wiring pattern 3 is formed by arranging detection electrodes having a predetermined area and connecting them through a coupling portion, and parasitic capacitance occurs when touched with a finger. The capacitance changes. By detecting this change in capacitance and specifying the corresponding X wiring pattern 2 and Y wiring pattern 3, the coordinates of the position touched by the finger are specified.

  A conductive film 5 is formed on the entire other surface of the transparent substrate 1. By forming the conductive film 5 on the back surface of the transparent substrate 1, a so-called shielding effect can be obtained. For example, even when the liquid crystal display device is arranged around, it is hardly affected by noise from the liquid crystal display device. Become. Further, the surface of the Y wiring pattern 3 on the side where the X wiring pattern 2 and the Y wiring pattern 3 of the transparent substrate 1 are formed is covered with a protective film 6 to protect the surface.

  Next, the electrode pattern of the detection electrode constituting the X wiring pattern 2 and the Y wiring pattern 3 will be described. As described above, the X wiring pattern 2 arranged in the X-axis direction and the Y wiring pattern 3 arranged in the Y-axis direction both have a detection electrode in a predetermined direction (the X wiring pattern 2 via the coupling portion). Are configured by connecting individual detection electrodes 7 to be described later in the Y-axis direction, and the Y wiring pattern 3 by connecting individual detection electrodes 8 in the X-axis direction. The detection electrode is usually a transparent electrode.

  In the following, it is assumed that the vertical and horizontal dimensions (X-axis direction and Y-axis direction) of the touch panel are different. Here, the dimension in the horizontal direction (X-axis direction) is large, and the dimension in the vertical direction (Y-axis direction) is small. That is, the length of the X wiring pattern 2 (line length of the detection electrode in the Y-axis direction) is shorter than the length of the Y wiring pattern 3 (line length of the detection electrode in the X-axis direction). .

  First, an example of an electrode pattern (conventional pattern) in which the area of the detection electrode constituting the X wiring pattern 2 and the area of the detection electrode constituting the Y wiring pattern 3 are equal will be described. FIG. 2 shows an example of a conventional pattern. In the electrode pattern shown in FIG. 2, as shown in FIG. 3A, the number of line-like wirings (X wiring pattern 2) arranged in the X-axis direction is six from X1 to X6, and FIG. As shown in FIG. 4, the number of line-shaped wirings (Y wiring pattern 3) arranged in the Y-axis direction is four, Y1 to Y4.

  These line-shaped X wiring pattern 2 and Y wiring pattern 3 are connected to the detection electrode 7 or the detection electrode 8 having a rhombus shape (a shape obtained by rotating a square by 45 °) via the coupling portion 9 or the coupling portion 10. And configured as one electrode (wiring). The detection electrode 7 constituting the X wiring pattern 2 and the detection electrode 8 constituting the Y wiring pattern 3 have the same shape and the same area.

  In the touch panel formed in such a manner that the X wiring pattern 2 and the Y wiring pattern 3 are orthogonal to each other, an X wiring pattern in which the electrostatic capacity change is detected by detecting a capacitance change due to a parasitic capacitance caused by touching a finger. By specifying the 2 and Y wiring patterns 3 from X1 to X6 and Y1 to Y4, it is possible to detect absolute coordinates. Further, as described above, a touch panel that detects the absolute coordinates of XY can also detect multiple points simultaneously.

In the touch panel having the electrode pattern shown in FIG. 2, the area Sx of the entire X wiring pattern 2 is the entire Y wiring pattern 3 when the area of one wiring is ignored while ignoring the area of each coupling portion 9, 10. It is represented by the following formula using the area Sy.
Sx = 4/6 · Sy

  That is, the area Sy of the Y wiring pattern 3 is 150% (1.5 times) the area Sx of the X wiring pattern 2 based on the difference in the number of lines, and the conductive film which is a shield layer as in the example shown in FIG. When 5 is formed, the parasitic capacitance with the conductive film 5 is about 50% larger in the Y wiring pattern 3 than in the X wiring pattern 2. Each value of the area ratio, in other words, the parasitic capacitance ratio, varies depending on the vertical / horizontal dimension ratio of the touch panel. Therefore, there is always a difference in the detected capacitance between the X wiring pattern 2 and the Y wiring pattern 3, which hinders measurement of capacitance change.

  Therefore, in the touch panel of the present embodiment, as shown in FIG. 4, the shape and area of the detection electrode 7 constituting the X wiring pattern 2 and the detection electrode 8 constituting the Y wiring pattern 3 are changed to change the X wiring pattern. 2, the difference in parasitic capacitance is suppressed by reducing the area difference between the entire area Sx and the entire area Sy of the Y wiring pattern 3, and there is no difference in detection capacitance between the X wiring pattern 2 and the Y wiring pattern 3. I am doing so. As a result, it is possible to measure the capacitance change with high accuracy and to accurately detect the coordinates.

  In the case of the present embodiment, the detection electrode 7 of the X wiring pattern 2 is expanded in area by enlarging a part of the rhombus as shown in FIG. As shown in FIG. 5B, the area of 8 is reduced by cutting out a part of the rhombus. FIG. 6 is an enlarged view of the shape of each of the detection electrodes 7 and 8, and the detection electrode 7 of the X wiring pattern 2 has a bottom of the dimension a when the dimension of one side of the rhombus is 3a. The protruding electrode 7a having a right isosceles triangular shape is integrally formed outwardly at the center of each side of the basic rhomboid electrode pattern. On the other hand, the detection electrode 8 of the Y wiring pattern 3 has a portion corresponding to the protruding electrode 7a of a right-angled isosceles triangle having a base of the dimension a when the dimension of one side of the rhombus is 3a. The shape is deleted from the central part of the side. In the case of this embodiment, in consideration of the arrangement efficiency of the wiring pattern, the notch portion of the detection electrode 8 of the Y wiring pattern 3 is arranged opposite to the protruding electrode 7a of the detection electrode 7 of the X wiring pattern 2. ing.

In the case of such an electrode shape, when comparing the area Sx of the entire X wiring pattern 2 and the area Sy of the entire Y wiring pattern 3 ignoring the areas of the coupling portions 9 and 10, the area Sx of the entire X wiring pattern 2 is The area Sy of the entire Y wiring pattern 3 is expressed by the following formula.
Sx = 22/21 ・ Sy

  In other words, in this case, the area Sx of the entire X wiring pattern 2 is 105% (1.05 times) of the area Sy of the entire Y wiring pattern 3 based on the differences in the areas of the detection electrodes 7 and 8 and the number of lines. Even when the conductive film 5 as the shield layer is formed as in the example shown in FIG. 1, the parasitic capacitance difference between the X wiring pattern 2 and the Y wiring pattern 3 can be kept small. is there.

  According to an experiment conducted by the present inventors, if the area difference between the area Sx of the entire X wiring pattern 2 and the area Sy of the entire Y wiring pattern 3 is 20% or less, the parasitic capacitance difference is sufficiently suppressed, and the capacitance It was found that change measurement (coordinate detection) can be accurately performed.

  In this embodiment, the X wiring pattern 2 is a lower layer and the Y wiring pattern 3 is an upper layer, but either the X wiring pattern 2 or the Y wiring pattern 3 may be an upper layer. However, when considering sensitivity and the like, as in this embodiment, the wiring with a small area of the detection electrode (Y wiring pattern 3 here) is the upper layer and the wiring with a large area of the detection electrode (here X wiring) The pattern 2) is preferably the lower layer from the viewpoint of detection sensitivity. Further, the detection electrodes 7 and 8 of the X wiring pattern 2 and the Y wiring pattern 3 can be formed in the same layer, and only the coupling portions 9 and 10 can be formed so as to intersect via the insulating layer 4. In the case of the embodiment, the detection sensitivity of the X wiring pattern 2 and the Y wiring pattern 3 can be made equal.

  By the way, in the touch panel described above, it is generally necessary to increase the number of electrodes in order to make the position detection accuracy equal even when the effective area size becomes large. To increase the effective area size without increasing the number of electrodes, it is necessary to increase the dimensions of the detection electrodes 7 and 8 constituting the X wiring pattern 2 and the Y wiring pattern 3. However, when the dimensions of the detection electrodes 7 and 8 constituting the X wiring pattern 2 and the Y wiring pattern 3 are enlarged, only one detection electrode 7 (or the detection electrode 8) comes into contact when a finger is touched. there is a possibility. Therefore, in order to increase the effective area size without increasing the number of electrodes and maintain the interval between the X wiring pattern 2 and the Y wiring pattern 3, it is necessary to develop a dedicated detection circuit, which takes time for development, etc. Problems occur.

  In order to solve such a problem, the shape of the detection electrode 7 of the X wiring pattern 2 and the detection electrode 8 of the Y wiring pattern 3 is devised. For example, as shown in FIG. It is preferable that at least a part of the electrode 7 for detection and the detection electrode 8 of the Y wiring pattern 3 is always in a circle with a diameter b (in a contact area assumed when a finger is touched).

  For example, based on the configuration shown in FIG. 7, the notched portions 71 are formed by notching inward the opposite side portions in the X direction of the detection electrodes 7 of the basic X wiring pattern 2. In order to make up for the electrode area removed by this step, the auxiliary electrode 72 is formed by extending the protruding electrode 7a adjacent to the notch 71 in the protruding direction. Due to the presence of the cutout portion 71 and the auxiliary electrode 72, the relative area as the detection electrode 7 is configured to be substantially equal to the area of the detection electrode 7 in the embodiment described with reference to FIG. On the other hand, the detection electrode 8 of the Y wiring pattern 3 is an auxiliary electrode in order to avoid the overlapping of the detection electrode 8 of the basic Y wiring pattern 3 with the auxiliary electrode 72 formed to protrude from the detection electrode 7. A portion facing 72 is cut out inward to form a cutout portion 81. In order to compensate for the electrode area removed by the notch 81, the end of the detection electrode 8 adjacent to the notch 81 extends along the outside of the auxiliary electrode 72 formed on the detection electrode 7, The auxiliary electrode 82 is arranged so that the tip portion is located in the notch 71 formed in the detection electrode 7. In this way, a part of the detection electrode 8 constituting the Y wiring pattern 3 is mixed in the basic configuration region of the detection electrode 7 constituting the X wiring pattern 2, while the detection electrode 8 constituting the Y wiring pattern 3. The detection electrodes 7 and 8 are inserted in a mixed manner so that a part of the detection electrodes 7 constituting the X wiring pattern 2 is mixed in the basic configuration area. With this configuration, since at least a part of each of the detection electrodes 7 and 8 is present in the contact area of the finger, the contact position can be reliably detected. The shape of the detection electrodes 7 and 8 including the auxiliary electrodes 72 and 82 is not limited to the illustrated case, and can be freely set as long as the relative area ratio of the detection electrodes 7 and 8 does not change. Needless to say.

  Assuming that the finger is touched, the diameter b is preferably set to about 15 mm in consideration of the normal finger size, and the detection electrode 7 of the X wiring pattern 2 and the Y wiring are set in a circle having a diameter of 15 mm. If the pattern detection electrode 8 is present, the position can be detected. Further, when devising the shapes of the detection electrode 7 of the X wiring pattern 2 and the detection electrode 8 of the Y wiring pattern 3, the detection electrode 7 of the X wiring pattern 2 and the detection electrode 8 of the Y wiring pattern 3 It is preferable to have a shape that suppresses an increase in parasitic capacitance.

  In the electrostatic capacitance detection type touch panel configured as described above, even if the vertical and horizontal dimensions are different, the detection electrode 7 of the X wiring pattern 2 and the detection electrode 8 of the Y wiring pattern 3 are touched when a finger is touched. The parasitic capacitance difference can be suppressed, and coordinate detection with high accuracy is possible. Also, simultaneous detection of a plurality of points is possible, and a touch panel having high transmittance can be configured by using the detection electrode 7 of the X wiring pattern 2 and the detection electrode 8 of the Y wiring pattern 3 as transparent electrodes. Is possible. Further, if the conductive film 5 is formed on the opposite surface of the transparent substrate 1, a shielding effect can be obtained, and the influence of noise due to the arrangement of the liquid crystal display device or the like can be avoided.

  As mentioned above, although embodiment of the electrostatic capacitance detection system touch panel to which this invention is applied was described, this invention is not limited to the said embodiment, In the range which does not deviate from the summary of this invention, it can change suitably. Needless to say. For example, the shapes of the detection electrodes 7 and 8 can be arbitrarily designed. Also, the number of arrangements of the X wiring pattern 2 and the Y wiring pattern 3 is arbitrary. In addition, the conductive film 5 disposed on the back side of the transparent substrate 1 can be omitted.

DESCRIPTION OF SYMBOLS 1 Transparent substrate, 2 X wiring pattern, 3 Y wiring pattern, 4 Insulating layer, 5 Conductive film, 6 Protective film, 7, 8 Detection electrode, 9,10 Joint part

Claims (5)

A capacitance detection system having a wiring pattern in which a plurality of detection electrodes having the same shape are arranged in a line on the same surface in the X-axis direction and the Y-axis direction orthogonal to each other on one surface of a transparent substrate A touch panel,
The line length of the detection electrode is different in the X-axis direction and the Y-axis direction, and the area of each detection electrode in the long line length direction is larger than the area of each detection electrode in the short line length direction. Capacitance detection type touch panel characterized by being small.   The difference between the area of the wiring pattern formed by connecting the detection electrodes arranged in the X-axis direction and the area of the wiring pattern formed by connecting the detection electrodes arranged in the Y-axis direction is 20%. The electrostatic capacitance detection type touch panel according to claim 1, wherein:   The wiring pattern is arranged so that both detection electrodes arranged in the X-axis direction and detection electrodes arranged in the Y-axis direction exist in a finger contact area. Or the electrostatic capacitance detection system touch panel of 2.   The detection electrodes arranged in the X-axis direction and the detection electrodes arranged in the Y-axis direction are laminated via an insulating layer, the detection electrode having a small area is the upper layer, and the detection electrode having a large area is the lower layer The capacitive touch panel according to any one of claims 1 to 3, wherein the touch panel is laminated so as to become.   5. The electrostatic capacitance detection type touch panel according to claim 1, wherein a conductive film is formed on a surface opposite to the transparent substrate.

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