JP2011238146A - Touch panel and display device equipped therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a touch panel and a display device using the same capable of reducing influences of parasitic capacitance and wiring resistance of detecting wires thereby enhancing the response and achieving stable touch coordinates.SOLUTION: In a touch screen 1, switch circuits 21a and 21b are controlled to select at different timing two detecting wires opposing each other at a dividing portion, e.g. a first left line detection wire WyL(1) and a first right line detection wire WyR(1) in line detecting wires 7a and 7b in divided right/left detection areas DL and DR. Also, a switch circuit 20a and a switch circuit X(R)20b are controlled to select at different timing two detecting wires neighboring each other along a longitudinal direction of a dividing portion e.g. a fourth row detection wire WxL(4) and a first row detection wire WxR(1) in row detection wires 6a and 6b.

Description

  The present invention relates to a touch panel and a display device including the touch panel.

  The touch panel is a device that detects a touch with a finger or the like and identifies its position coordinates. The touch panel is attracting attention as one of excellent user interface means. Various types of touch panels such as a resistive film type and a capacitance type have been commercialized.

  As a capacitive touch panel, a projection type that can detect touch even when the front side of a touch screen with a built-in touch sensor is covered with a protective plate such as a glass plate with a thickness of several millimeters. There is a capacitive touch panel (see, for example, Patent Document 1). This type of touch panel has advantages such as the fact that the protective plate can be placed on the front surface, so it is excellent in robustness, can detect touch even when wearing gloves, and has a long life because there is no moving part. Yes.

  The touch screen constituting the touch panel described in Patent Document 1 has a first series conductor element formed on a thin dielectric film as a detection conductor for detecting capacitance, and is insulated on the first series conductor element. And a second series of conductor elements formed with a membrane therebetween. There is no electrical contact between the conductor elements, and a plurality of intersections are formed. The most suitable material for the conductor element is a metal material such as silver. In addition, the visibility of the display becomes a problem, and in order to reduce the visibility, indium tin oxide (abbreviation: ITO) is used as a material of the conductor element. Moreover, it can replace with a conductor element and can use a thin lead wire of 10-20 micrometers.

  The conductor element for detecting the electrostatic capacitance is connected to the capacitance control oscillator via the output line and the multiplexer circuit. The output of the capacity control oscillator is counted by a divider and used as capacity detection data. Furthermore, the touch position between the conductor elements can be interpolated by the detected capacitance relative value of one or more conductor elements.

  The parasitic capacitance of the detection wiring such as the detection circuit such as the capacitance control oscillator and the conductor element, and the resistance of the detection wiring influence the detection time and detection sensitivity of the touch on the touch screen, and the response and coordinate accuracy of the touch panel. Since this influence becomes more prominent as the touch screen becomes larger, there is a problem that it is difficult to enlarge the touch screen.

  For example, the resistance of the detection wiring increases with an increase in the size of the touch screen, so that there is a problem that the influence on the detection time and the detection sensitivity is increased. A technique for solving this problem is disclosed in Non-Patent Document 1. The touch screen of the touch panel disclosed in Non-Patent Document 1 is formed in a horizontally long shape, and is a row direction (hereinafter referred to as “hereinafter referred to as“ X direction ”) that is a vertical direction compared to a column direction that is a horizontal direction (hereinafter sometimes referred to as“ X direction ”). The length dimension of the sensor that is the detection wiring (hereinafter sometimes referred to as “sensor length”) is longer in the case of “Y direction”.

  In the touch screen disclosed in Non-Patent Document 1, in the Y direction, which is the long row direction of the sensor, the sensor, which is the detection wiring, is divided into two parts to the left and right to reduce the wiring resistance. The XY sensors in the two left and right areas are independent so as to scan continuously. This reduces the resistance difference between the sensor in the X direction, which is the column direction, and the sensor in the Y direction, which is the row direction, and improves the scan rate of the sensor.

JP-T 9-51186 (page 7, line 19 to page 8, line 4, page 8, line 23 to page 9, line 6, page 13, line 4 to line 12, page 13, line 23 to page 14) Page 10 line, FIG. 1, FIG. 2, FIG. 6, FIG. 8)

IDW'09 (THE 16TH INTERNATIONAL DISPLAY WORKSHOPS) Proceedings, December 2009, p. 2156 (Left column 1 line-Right column 11 line, Fig. 6, 7)

  In the touch screen disclosed in Non-Patent Document 1 described above, the detection wiring in the row direction, which is the Y direction, is divided into two to reduce the wiring resistance. In such a touch screen divided into left and right, in order to shorten the detection time, when the left and right detection wirings are simultaneously scanned and detected, there arises a problem that the left and right detection systems interfere with each other.

  As described above, when the area of the touch screen is divided and each area is scanned and detected simultaneously in order to shorten the detection time, there is a problem that the detection system of each area interferes. However, Non-Patent Document 1 does not disclose any solution for the problem that the detection system of each region interferes.

  An object of the present invention is to provide a touch panel that suppresses the influence of parasitic capacitance and wiring resistance of a detection wiring, has high responsiveness, and can obtain stable touch coordinates, and a display device using the touch panel.

  The touch panel of the present invention has a plurality of detection areas divided by a dividing portion extending in a predetermined row direction or column direction, and each detection area is provided for a plurality of detections arranged in the row direction and the column direction. A touch screen having wiring, a switch circuit that sequentially selects the plurality of detection wirings in parallel in the plurality of detection regions, the detection wiring selected by the switch circuit, and the touch screen Based on the detection result of the electrostatic capacitance detection circuit that detects the electrostatic capacitance formed between the indicator and the electrostatic capacitance detection circuit, touch coordinates representing the position of the indicator on the touch screen are calculated. Touch coordinate calculation circuit, and the switch circuit selects two detection wirings that are adjacent to each other with the end portions facing each other in the division unit at different timings. And wherein the door.

  Further, the touch panel of the present invention has a plurality of detection areas divided by a dividing portion extending in a predetermined row direction or column direction, and each detection area is provided with a plurality of detections arranged in the row direction and the column direction. A touch screen having a wiring for use, a switch circuit for sequentially selecting the plurality of detection wirings in parallel in the plurality of detection regions, the detection wiring selected by the switch circuit, and a proximity to the touch screen A capacitance detection circuit for detecting a capacitance formed between the indicator and the touch coordinate indicating the position of the indicator on the touch screen based on a detection result of the capacitance detection circuit. A touch coordinate calculation circuit for calculating, and the switch circuit connects the two detection wirings adjacent to each other along the extending direction of the division unit in the division unit. And selecting at ring.

  Moreover, the display device of the present invention includes the touch panel and a display panel attached to the touch screen of the touch panel.

  According to the touch panel of the present invention, the switch circuit selects two detection wirings that are adjacent to each other with the terminal portions facing each other at different timings. It is possible to prevent the detection wiring from being selected at the same time and detecting the capacitance. As a result, when the indicator such as a finger touches the touch screen, the capacitance between one of the detection wires and the indicator of the two detection wires adjacent to each other with the terminal portions facing each other in the divided portion. When the is formed, it is possible to prevent the formed capacitance from being detected as a capacitance formed between the other detection wiring and the indicator and appearing as a false detection value. . Therefore, since interference between a plurality of detection areas can be suppressed, a stable touch coordinate calculation result can be obtained without causing an erroneous determination as to whether or not a touch has occurred due to the indicator.

  According to the touch panel of the present invention, since the switch circuit selects two detection wirings adjacent to each other along the extending direction of the dividing portion at different timings, the dividing portion extends in the extending direction of the dividing portion. It is possible to prevent two detection wirings adjacent to each other from being selected at the same time and detecting a capacitance. As a result, when the indicator such as a finger touches the touch screen, the divided portion is arranged between one of the two detection wires adjacent to the extending direction of the divided portion and the indicator. When the electrostatic capacitance is formed on the capacitor, the formed electrostatic capacitance is detected as the electrostatic capacitance formed between the other detection wiring and the indicator and appears as a false detection value. Can be prevented. Therefore, since interference between a plurality of detection areas can be suppressed, a stable touch coordinate calculation result can be obtained without causing an erroneous determination as to whether or not a touch has occurred due to the indicator.

  According to the display device of the present invention, the display device is configured by including the above-described touch panel and display panel of the present invention. Accordingly, it is possible to realize a display device having a touch panel function capable of obtaining a stable touch coordinate calculation result without suppressing interference between a plurality of detection areas of the touch screen of the touch panel and causing erroneous determination of whether or not a touch has occurred. be able to.

It is a top view which shows the structure of the touch screen 1 in the touchscreen which is the 1st Embodiment of this invention. FIG. 2 is a perspective sectional view showing a configuration of a part of the touch screen 1 shown in FIG. 1. It is a figure which shows typically the whole structure of the touch panel 100 which is the 1st Embodiment of this invention. 2 is a block diagram illustrating configurations of a touch screen 1 and a detection processing circuit 19. FIG. The configuration of the left column wiring switch circuit X (L) 20a, the left row wiring switch circuit Y (L) 21a, the right column wiring switch circuit X (R) 20b, and the right row wiring switch circuit Y (R) 21b shown in FIG. FIG. It is a figure which shows typically the condition in the case of performing each detection operation in left detection area | region DL and right detection area | region DR in parallel. 4 is an equivalent circuit diagram showing an equivalent circuit of a left detection region DL and a right detection region DR when a touch capacitance is formed on the touch screen 1. FIG. It is a figure which shows typically the scanning order of the row detection wiring 7 in the touchscreen of the 1st Embodiment of this invention. FIG. 3 is an equivalent circuit diagram illustrating an equivalent circuit of a left detection region DL and a right detection region DR when a touch capacitance is formed on the touch screen 1 according to the first embodiment of the present invention. It is a timing chart which shows the scan sequence of the detection wiring in the 1st Embodiment of this invention. It is a timing chart which shows the scan sequence of the detection wiring in the 1st Embodiment of this invention. FIG. 6 is a diagram for explaining a coupling capacitance Ccx between column detection wirings 6a and 6b in a divided portion of the left detection region DL and the right detection region DR of the touch screen 1. It is a figure which shows the structure of the left column wiring switch circuit X (L) 20a in the 2nd Embodiment of this invention. It is a timing chart which shows the scan sequence of the detection wiring in the 2nd Embodiment of this invention. It is a timing chart which shows the scan sequence of the detection wiring in the 2nd Embodiment of this invention. It is a figure which shows the structure of the left column wiring switch circuit X (L) 20a in the 3rd Embodiment of this invention. It is a figure which shows the structure of the right column wiring switch circuit X (R) 20b in the 3rd Embodiment of this invention. It is a timing chart which shows the scan sequence of the detection wiring in the touch panel of the 3rd Embodiment of this invention. It is a timing chart which shows the scan sequence of the detection wiring in the touch panel of the 3rd Embodiment of this invention. It is sectional drawing which shows the structure of the liquid crystal display device which is the 4th Embodiment of this invention. It is a characteristic view which shows an example of the relationship between the electrostatic capacitance connected to the relaxation oscillation circuit used for the touch panel which is the premise technique of this invention, and an oscillation period. It is a figure which shows the relationship between an oscillation period and detection time.

<Prerequisite technology>
FIG. 21 is a characteristic diagram showing an example of the relationship between the capacitance connected to the relaxation oscillation circuit used in the touch panel, which is a prerequisite technology of the present invention, and the oscillation period. FIG. 22 is a diagram illustrating the relationship between the oscillation period and the detection time.

  The touch panel includes a touch screen in which detection wirings are arranged in a matrix, and a detection circuit that detects contact of an indicator with the touch screen, that is, a touch. The detection wiring is connected to a capacitance control oscillator, which is a detection circuit, via an output line and a multiplexer circuit.

  As the capacity control oscillator, for example, a relaxation oscillation circuit can be used. The oscillation period of the relaxation oscillation circuit is determined according to, for example, a time constant due to charging / discharging of the resistance element and the capacitance element. The relaxation oscillation circuit detects a change in capacitance (hereinafter referred to as “touch capacitance”) formed between an indicator such as a finger and the detection wiring of the touch screen as a change in oscillation cycle.

  The relationship between the capacitance connected to the relaxation oscillation circuit and the oscillation cycle has a linear characteristic as shown in FIG. A detection value for the touch capacitance can be obtained by integrating the oscillation cycle deviation when the touch capacitance is generated for a predetermined oscillation cycle, that is, for a predetermined number N. At this time, the oscillation period deviation when the touch capacitance Ct occurs is constant regardless of the values of other capacitances, for example, the parasitic capacitances of the detection circuit and the detection wiring.

  However, as shown in FIG. 22, the oscillation period increases as the capacitance connected to the detection end of the relaxation oscillation circuit increases. Therefore, when the electrostatic capacitance that becomes a parasitic capacitance increases, the detection time required to obtain a desired detection value for the touch capacitance also increases as shown in FIG. As a result, the response time from when the touch screen is touched by the user's finger or the like until the touch coordinate data is output from the touch panel also increases, and the responsiveness to the touch decreases. Alternatively, when the number of times of oscillation cycle integration is reduced in order to satisfy a desired detection time, the detection value for the touch capacitance is reduced. That is, the detection sensitivity with respect to the touch capacitance is reduced, and the accuracy of the touch coordinate data calculated based on the detection value is reduced.

  The electrostatic capacitance that is a parasitic capacitance at the detection end of a detection circuit such as a relaxation oscillation circuit may be referred to as a capacitance of a cross portion (hereinafter, referred to as a “cross portion capacitance”) that is an intersection of detection wirings provided in the matrix direction. ), And a parasitic capacitance included in the multiplexer circuit that switches the connection between the detection wiring and the detection circuit.

  The resistance value of the detection wiring also affects the detection sensitivity of the touch capacitance. For example, when touching a portion of the detection wiring extending in the matrix direction near the detection circuit, that is, a portion on the connection terminal side of the touch screen and the detection circuit, and when touching a portion far from the detection circuit, the touch capacitance Detection value is different. Specifically, when the same touch capacitance is formed in the latter case where a larger detection wiring resistance is interposed between the touch capacitance and the detection circuit, that is, when a portion far from the detection circuit is touched Even so, the detection value of the touch capacitance by the detection circuit becomes small.

  Thus, a decrease in detection sensitivity is seen from the connection terminal side to the anti-connection terminal side, that is, the side far from the connection terminal. In other words, a detection sensitivity deviation occurs depending on the touch position. That is, the detection sensitivity and response time greatly depend on the parasitic capacitance and the detection wiring resistance at the detection end of the detection circuit. This applies similarly even when a detection method other than the relaxation oscillation method is used.

  However, the touch capacitance is formed only about several pF at most. In particular, when a glass plate or the like is provided on the front surface of the touch screen to ensure robustness, the touch capacity further decreases. Accordingly, the response time increases as the detection time for obtaining a desired detection value increases. Alternatively, the detection value decreases to satisfy the desired response time. And the precision of the touch coordinate data calculated based on this detection value falls.

  The parasitic capacitance of the multiplexer circuit that switches the connection between the detection wiring and the detection end of the detection circuit as the parasitic capacitance of the detection circuit is, for example, increased when the number of detection wiring increases as the touch screen increases in size. It increases with the increase. Furthermore, in order to reduce the noise from the display device used in combination on the back side of the touch screen, when the electrostatic shield surface is provided on the back side of the detection wiring of the touch screen, Parasitic capacitance also increases. Particularly when the touch screen is increased in size, the parasitic capacitance of the detection wiring increases as the wiring length of the detection wiring increases.

  As described above, the parasitic capacitances of the detection circuit and the detection wiring, and the resistance of the detection wiring influence the touch detection time and detection sensitivity on the touch screen, and thus the touch panel response and coordinate accuracy. Since this influence becomes more prominent as the touch screen becomes larger, it becomes a problem for the enlargement of the touch screen.

  In order to suppress the influence of the resistance of the detection wiring, for example, the detection wiring in the row direction may be divided into two to reduce the wiring resistance. In such a touch screen divided into two parts, in order to shorten the detection time, when the detection wiring of each divided area is scanned and detected simultaneously, the detection system of each area interferes, and the occurrence of touch occurs. There is a problem that erroneous determination of presence or absence occurs. Therefore, in the present invention, the configurations of the following embodiments are employed.

<First Embodiment>
FIG. 1 is a plan view showing a configuration of a touch screen 1 in a touch panel according to a first embodiment of the present invention. The touch screen 1 includes a plurality of detection column wirings 2 and a plurality of detection row wirings 3. The plurality of detection column wirings 2 extend in the column direction, in the vertical direction toward the paper surface in FIG. 1, and are arranged in parallel in the row direction at a predetermined pitch and in the horizontal direction in FIG. . The plurality of detection row wirings 3 extend in the row direction and are arranged in parallel in the column direction at a predetermined pitch.

  In the present embodiment, a plurality of, for example, a predetermined number of detection column wirings 2 are electrically connected in common by the column connection wirings 4 at one end and the other end, respectively, at the upper end and the lower end in FIG. Thus, a bundle of detection column wiring groups 6 is configured. Similarly, a plurality of, for example, a predetermined number of detection row wires 3 are electrically connected in common by the row connection wires 5 at one end and the other end, respectively, at the left end and the right end in FIG. A bundle detection row wiring group 7 is formed. Therefore, a slit-shaped opening is formed between the detection column wirings 2 of each detection column wiring group 6. Similarly, a slit-shaped opening is formed between the detection row wirings 3 of each detection row wiring group 7.

  In FIG. 1, a bundle of detection column wiring groups 6 includes five detection column wirings 2, and a bundle of detection row wiring groups 7 includes five detection row wirings 3. Configured.

  In the touch screen 1, a row direction in which the detection row wiring group 7 extends is defined as “x-axis direction”, and a column direction in which the detection column wiring group 6 extends is defined as “y-axis direction”. Is defined. The detection row wiring group 7 and the detection column wiring group 6 are orthogonal to each other, and the x-axis direction and the y-axis direction are orthogonal to each other. In the following description, the row direction may be referred to as “row direction x” and the column direction may be referred to as “column direction y”.

  In the present embodiment, a plurality of, for example, a predetermined number of detection column wiring groups 6 are arranged in parallel in the row direction x at intervals. Similarly, a plurality of, for example, a predetermined number of detection row wiring groups 7 are arranged in parallel at intervals in the column direction y. In FIG. 1, the detection column wiring group 6 and the detection row wiring group 7 (hereinafter, the detection column wiring group 6 and the detection row wiring group 7 are collectively referred to as “detection wiring group” or “detection bundle wiring”). However, as described later, in the present embodiment, the predetermined number of the detection wiring groups 6 and 7 is 8 respectively. Hereinafter, each of the detection wiring groups 6 and 7 may be referred to as a system, and the predetermined number of the detection wiring groups 6 and 7 may be referred to as a system number. In other words, in the present embodiment, the detection wiring groups 6 and 7 have eight systems in the row direction x and the column direction y, respectively.

  The detection wiring groups 6 and 7 are connected to the terminal 10 by lead wirings 8 and 9. In the present embodiment, when the indicator touches the touch screen 1, the detection column wiring 2 and the detection row wiring 3 (hereinafter referred to as the detection column wiring 2 and the detection wiring) constituting the detection wiring groups 6 and 7. A touch capacitor is formed between the indicator and the row wiring 3 as a generic term “detection wiring”. The number and the wiring pitch of the detection wiring groups 6 and 7 and the number, the wiring width and the wiring pitch of the detection wirings 2 and 3 constituting the detection wiring groups 6 and 7 are determined by the touch position of the indicator on the touch panel. Specifically, the touch position is appropriately selected from the required resolution of the coordinate value on the touch screen 1 (hereinafter sometimes referred to as “touch coordinate value”).

  Here, in place of each of the detection wiring groups 6 and 7 constituted by a plurality of detection wirings 3 and 4, if a wiring constituted by a so-called solid wiring having no opening in the wiring is provided, the touch Large capacity can be secured. However, when a touch panel is used in front of the display panel, the solid wiring is a factor that prevents transmission of light used for display on the display panel (hereinafter sometimes referred to as “display light”). As a result, the transmittance of display light is reduced. Therefore, in the present embodiment, the detection wiring groups 6 and 7 are configured by the plurality of detection wirings 2 and 3 as described above, and the area of the slit-shaped opening between the detection wirings 2 and 3 is determined. Is set to a large value to suppress a decrease in the transmittance of the display light. However, a modification in which a single wiring, which is a so-called solid wiring, is provided instead of the detection wiring groups 6 and 7 may be applied in view of the problem of a decrease in the transmittance of display light. .

  FIG. 2 is a perspective sectional view showing a configuration of a part of the touch screen 1 shown in FIG. 2 corresponds to a perspective view of the touch screen 1 shown in FIG. 1 as viewed obliquely from the front side of the drawing in FIG. 1, and shows a layer structure in the thickness direction of the touch screen 1.

  The touch screen 1 includes a translucent transparent substrate (hereinafter referred to as “base substrate”) 12, an interlayer insulating film 13, and a protective film 14. The base substrate 12 is a layer constituting a surface on one side in the thickness direction of the touch screen 1. More specifically, the base substrate 12 has translucency and insulation, and is made of an insulating material having translucency such as transparent glass and transparent resin. In the present embodiment, the base substrate 12 is made of transparent glass.

  On the surface on the other side in the thickness direction of the base substrate 12, the plurality of detection column wirings 2 are formed, and the detection column wiring group 6 is configured by the detection column wirings 2. The detection column wiring 2 is composed of a conductive film made of a conductive material. Examples of the conductive material include metal wiring materials such as copper (Cu) and aluminum (Al), and light-transmitting conductive materials (hereinafter sometimes referred to as “transparent wiring material”) such as ITO. In the present embodiment, a transparent wiring material is used as the conductive material, and the detection column wiring 2 is realized by a transparent wiring made of a transparent wiring material.

  A transparent interlayer insulating film 13 is formed on the other side in the thickness direction of the base substrate 12, and below the base substrate 12 in FIG. The interlayer insulating film 13 has a light-transmitting property and an insulating property and is made of a light-transmitting insulating material such as silicon nitride (SiN). The plurality of detection row wirings 3 described above are formed on the surface of the interlayer insulating film 13 on the other side in the thickness direction, and the detection row wiring group 7 is configured by these detection row wirings 3. The detection row wiring 3 is made of the same conductive film as the detection column wiring 2. In the present embodiment, the detection row wiring 3 is realized by a transparent wiring in the same manner as the detection column wiring 2.

  Although different from the present embodiment, the arrangement positions of the detection column wirings 2 and the detection row wirings 3 in the thickness direction of the base substrate 12 are reversed, and the detection rows are formed on the surface of the base substrate 12 on the other side in the thickness direction. The wiring 3 may be formed, and the detection column wiring 2 may be formed on the surface of the interlayer insulating film 13 on the other side in the thickness direction. The detection wirings 2 and 3 may be realized not by a transparent wiring using a transparent wiring material such as ITO but by a metal wiring using a metal wiring material such as aluminum. In this case, as described above, the detection wiring groups 6 and 7 are constituted by the plurality of detection wirings 2 and 3, and the area of the slit opening between the detection wirings 2 and 3 is increased. By setting, the transmittance for display light can be secured.

  A transparent protective film 14 is formed on the other side in the thickness direction of the interlayer insulating film 13, that is, below the interlayer insulating film 13 in FIG. The protective film 14 has a light-transmitting property and an insulating property, and is made of a light-transmitting insulating material such as SiN, like the interlayer insulating film 13.

  FIG. 3 is a diagram schematically showing the overall configuration of the touch panel 100 according to the first embodiment of the present invention. The touch panel 100 includes the touch screen 1 shown in FIGS. 1 and 2, a flexible printed circuit (abbreviated as FPC) 17, and a controller substrate 18.

  A terminal provided at one end of the FPC 17 is mounted on the terminal 10 shown in FIG. 1 of the touch screen 1 by using an anisotropic conductive film (abbreviation: ACF) or the like. The terminals 10 of the touch screen 1 are not shown in FIG. A terminal provided at the other end of the FPC 17 is mounted on the controller board 18. Through the FPC 17, the ends of the detection wiring groups 6 and 7 of the touch screen 1 and the controller board 18 are electrically connected. As a result, the panel shown in FIG. 3 functions as the touch panel 100.

  The controller board 18 performs detection processing for calculating the touch position of the indicator, more specifically, the coordinates of the touch position on the touch screen 1 (hereinafter referred to as “touch coordinates”) based on the detection result of the touch capacitance. A circuit 19 is mounted. The touch coordinate value calculated by the detection processing circuit 19, that is, the touch coordinate value is output as detected coordinate data to an external computer (not shown).

  FIG. 4 is a block diagram illustrating configurations of the touch screen 1 and the detection processing circuit 19. 5 shows the left column wiring switch circuit X (L) 20a, the left row wiring switch circuit Y (L) 21a, the right column wiring switch circuit X (R) 20b and the right row wiring switch circuit Y (R) shown in FIG. It is a block diagram which shows the structure of 21b.

  The touch screen 1 of the present embodiment has a rectangular shape, and is arranged, for example, such that the longitudinal direction coincides with the row direction, that is, the left-right direction toward the paper surface of FIG. In the touch screen 1, as shown in FIG. 4, the detection region is divided into one region in the row direction and the other so that the detection row wiring group 7 having a large parasitic capacitance and detection wiring resistance is divided into two. The area is divided into two areas. That is, in FIG. 4, the detection area is divided into two parts, that is, a right area and a left area as viewed in the drawing. In the following description, the detection area on the left side of the paper surface of FIG. 4 that is one area in the row direction is referred to as “left detection area DL”, and is directed to the paper surface of FIG. 4 that is the other area in the row direction. The right detection area is referred to as “right detection area DR”. In the following description, the detection column wiring group 6 may be simply referred to as “column detection wiring”, and the detection row wiring group 7 may be simply referred to as “row detection wiring”. The column detection wiring 6 and the row detection wiring 7 may be collectively referred to as “detection wiring”.

  In the present embodiment, there are four detection column wiring groups 6 for touch detection in the left detection region DL, that is, four systems, specifically, the first to fourth left detection column wiring groups WxL shown in FIG. (1) to WxL (4), and six detection row wiring groups 7, that is, six systems, specifically, the first to sixth left detection row wiring groups WyL (1) to WyL (1) to FIG. It consists of WyL (6). In the following description, the first to fourth left detection column wiring groups WxL (1) to WxL (4) may be collectively referred to as “left detection column wiring group 6a” or “left column detection wiring 6a”. The first to sixth left detection row wiring groups WyL (1) to WyL (6) may be collectively referred to as “left detection row wiring group 7a” or “left row detection wiring 7a”.

  Also, there are four detection column wiring groups 6 for touch detection in the right detection region DR, that is, four systems, specifically, the first to fourth right detection column wiring groups WxR (1) to FIG. 4 shown in FIG. WxR (4) and six detection row wiring groups 7, that is, four systems, specifically, first to sixth right detection row wiring groups WyR (1) to WyR (6) shown in FIG. Consists of. In the following description, the first to fourth right detection column wiring groups WxR (1) to WxR (4) may be collectively referred to as “right detection column wiring group 6b” or “right column detection wiring 6b”. The first to sixth right detection row wiring groups WyR (1) to WyR (6) may be collectively referred to as “right detection row wiring group 7b” or “right row detection wiring 7b”.

  In the present embodiment, in order to facilitate understanding, the number of the detection column wiring groups 6 in the left detection region DL is four, and the number of the detection row wiring groups 7 in the right detection region DR is six. However, for example, when the pitch of the wiring group is set to about 7 mm in consideration of the touch size with a finger, when the screen size is 7 inches or more diagonally, the number of wiring groups is determined by the left detection area DL and the right detection. In the region DR, the number exceeds 10 each.

  As shown in FIG. 4, the detection processing circuit 19 shown in FIG. 3 has a left column wiring switch circuit X (L) 20a, a left row wiring switch circuit Y (L) 21a, and a right column wiring switch circuit X (R). 20b, right row wiring switch circuit Y (R) 21b, left capacitance detection circuit (L) 22a, right capacitance detection circuit (R) 22b, touch coordinate calculation circuit 23, detection control circuit 24, left buffer circuit 25a And a right buffer circuit 25b.

  In the left detection area DL of the touch screen 1, each of the left column detection wirings WxL (1) to WxL (4) is connected to the left column wiring switch circuit X (L) 20a, and each of the left row detection wirings WyL (1) to WyL. (6) is connected to the left row wiring switch circuit Y (L) 21a. In the right detection area DR of the touch screen 1, each of the right column detection wirings WxR (1) to WxR (4) is connected to the right column wiring switch circuit X (R) 20b, and each of the right row detection wirings WyR (1) to WyR. (6) is connected to the right row wiring switch circuit Y (R) 21b.

  The left column wiring switch circuit X (L) 20a and the left row wiring switch circuit Y (L) 21a are connected to the left capacitance detection circuit (L) 22a and the left buffer circuit 25a. The right column wiring switch circuit X (R) 20b and the right row wiring switch circuit Y (R) 21b are connected to the right capacitance detection circuit (R) 22b and the right buffer circuit 25b. The left buffer circuit 25a is connected to the left column wiring switch circuit X (L) 20a and the left row wiring switch circuit Y (L) 21a. The right buffer circuit 25b is connected to the right column wiring switch circuit X (R) 20b and the right row wiring switch circuit Y (R) 21b. The left capacitance detection circuit (L) 22 a and the right capacitance detection circuit (R) 22 b are connected to the touch coordinate calculation circuit 23. The detection control circuit 24 includes a left column wiring switch circuit X (L) 20a, a left row wiring switch circuit Y (L) 21a, a right column wiring switch circuit X (R) 20b, a right row wiring switch circuit Y (R) 21b, The left capacitance detection circuit (L) 22 a, the right capacitance detection circuit (R) 22 b, and the touch coordinate calculation circuit 23 are connected.

  The left column wiring switch circuit X (L) 20a includes a selector circuit 27 as shown in FIG. The selector circuit 27 is a switch circuit that switches the connection 2: 1. Hereinafter, a switch circuit that switches the connection to two-to-one like the selector circuit 27 may be referred to as a “two-to-one selector circuit”. In the left column wiring switch circuit X (L) 20a, the selector circuit 27 determines the connection destination of the left column detection wiring 6a, that is, the first to mth left detection column wiring groups WxL1 to WxLm for each column wiring group for detection 6. Then, switching to the first terminal a side connected to the left capacitance detection circuit (L) 22a or the second terminal b side connected to the left buffer circuit 25a is performed.

  Left row wiring switch circuit Y (L) 21a, right column wiring switch circuit X (R) 20b, and right row wiring switch circuit Y (R) 21b are the same as left column wiring switch circuit X (L) 20a shown in FIG. Each having a selector circuit 27.

  The left column detection wiring 6a and the left row detection wiring 7a in the left detection region DL are set in the subsequent stage by the selector circuit 27 of the corresponding left column wiring switch circuit X (L) 20a and left row wiring switch circuit Y (L) 21a. The connection is switched to the connection with the detection end (hereinafter sometimes referred to as “detection node”) of the left capacitance detection circuit (L) 22a or the connection with the output end of the left buffer circuit 25a. Further, the right column detection wiring 6b and the right row detection wiring 7b in the right detection region DR are caused by the selector circuit 27 of the right column wiring switch circuit X (R) 20b and the right row wiring switch circuit Y (R) 21b corresponding thereto. The connection is switched to the connection with the detection end of the subsequent right-side capacitance detection circuit (R) 22b or the connection with the output end of the right-side buffer circuit 25b.

  In the present embodiment, the selector circuit 27 of the left column wiring switch circuit X (L) 20a and the left row wiring switch circuit Y (L) 21a is connected in accordance with a control signal instruction given from the detection control circuit 24. Select. Specifically, the connection to the left capacitance detection circuit (L) 22a is sequentially switched one by one from the left column detection wiring 6a and the left row detection wiring 7a in the left detection region DL. That is, one detection wiring selected to be connected to the left capacitance circuit (L) 22a becomes a detection target as the selection detection wiring, and other detection wirings, that is, the left capacitance circuit (L) 22a. A detection wiring that is not selected for connection (hereinafter also referred to as “non-selected detection wiring”) is connected to the output terminal of the left buffer circuit 25a.

  Similarly, the selector circuit 27 of the right column wiring switch circuit X (R) 20b and the right row wiring switch circuit Y (R) 21b selects the connection according to the instruction of the control signal given from the detection control circuit 24. . Specifically, the connection to the right capacitance detection circuit (R) 22b is sequentially switched one by one from the right column detection wiring 6b and the right row detection wiring 7b in the right detection region DR. That is, one detection wiring selected to be connected to the right capacitance circuit (R) 22b becomes a detection target as the selection detection wiring, and other detection wirings, that is, the right capacitance circuit (R) 22b. The non-selected detection wiring whose connection is not selected is connected to the output terminal of the right buffer circuit 25b.

  The input end of the left buffer circuit 25a is connected to the detection end of the left capacitance detection circuit (L) 22a, and the input end of the right buffer circuit 25b is connected to the detection end of the right capacitance detection circuit (R) 22b. Is connected. Here, for example, as a capacitance detection circuit, a case is considered in which an RC circuit is configured including a capacitance to be measured, and a relaxation oscillator that detects a change in the time constant as a change in the oscillation period is used. In this case, the connection point between the resistive element and the capacitive element is the detection end. In addition, when the time for charging the constant current to the capacitive element is set as the oscillation period, the connection point between the constant current source and the capacitive element is the detection end.

  That is, for the non-selection detection wiring, the left column wiring switch circuit X (L) 20a, the left row wiring switch circuit Y (L) 21a, the right column wiring switch circuit X (R) 20b, and the right row wiring switch circuit Y (R ) 21b applies the voltages at the detection ends of the left and right capacitance detection circuits 22a and 22b as buffered voltages via the left and right buffer circuits 25a and 25b. In FIG. 4, the specific configuration of the left and right capacitance detection circuits 22a and 22b is not particularly shown, but a counting circuit is provided at the subsequent stage of the oscillation circuit, and the oscillation cycle varies depending on the size of the connected capacitive element. It is possible to obtain a capacitance detection value by accumulating the changing oscillation signal a predetermined number of times and measuring this time.

  The detection result of the capacitance corresponding to each detection wiring output from the left capacitance detection circuit (L) 22a and the right capacitance detection circuit (R) 22b is given to the touch coordinate calculation circuit 23 in the subsequent stage. The touch coordinate calculation circuit 23 touches the indicator on the touch screen 1 based on the detection results of the electrostatic capacitance provided from the left electrostatic capacitance detection circuit (L) 22a and the right electrostatic capacitance detection circuit (R) 22b. A touch coordinate value that is a coordinate value of the position is calculated. The touch coordinate value calculated by the touch coordinate calculation circuit 23 is output as detection coordinate data to a computer outside the detection processing circuit 19 or the like. Here, in calculating the touch coordinates, for example, when there is a detection wiring having a detection value exceeding a predetermined threshold, it is determined that there is a touch by an indicator such as a finger, and the detection value of the detection wiring adjacent thereto is detected. Also, the coordinates between the detection wirings are obtained by interpolation calculation.

  As described above, the detection area of the touch screen 1 according to the present embodiment is divided into the left detection area DL and the right detection area DR. The left column detection wiring 6a and the left row detection wiring 7a included in the left detection region DL are sequentially connected to the left capacitance detection circuit (L) 22a, respectively, and the left column wiring switch circuit X (L) 20a and The electrostatic capacitance formed between the detection wiring and the indicator such as a finger is detected by switching the selection with the left row wiring switch circuit Y (L) 21a. The detection voltage at the detection end of the left capacitance detection circuit (L) 22a is buffered and applied to the non-selection detection wiring via the left buffer circuit 25a.

  The right column detection wiring 6b and the right row detection wiring 7b included in the right detection region DR are sequentially connected to the right capacitance detection circuit (R) 22b, respectively, and the right column wiring switch circuit X (R) 20b and The capacitance formed between the detection wiring and an indicator such as a finger is detected by switching and selecting by the right-side wiring switch circuit Y (R) 21b. The detection voltage at the detection end of the right capacitance detection circuit (R) 22b is buffered and applied to the non-selection detection wiring via the right buffer circuit 25b.

  In such a configuration, the detection time can be shortened by detecting in parallel the capacitance formed in the detection wiring corresponding to each of the left detection region DL and the right detection region DR. Further, by dividing the detection area into the left detection area DL and the right detection area DR, the parasitic capacitance of the row detection wiring 7 whose wiring length is halved is approximately halved. The detection time is reduced accordingly. In addition, since the resistance values thereof are also reduced, it is more advantageous than the case where the detection region is not divided from the viewpoint of detection sensitivity.

  FIG. 6 is a diagram schematically illustrating a situation when the detection operations in the left detection region DL and the right detection region DR are performed in parallel. In FIG. 6, for example, the touch region T is formed by the touch of the indicator near the center of the intersection of the third left column detection wiring WxL (3) and the third left row detection wiring WyL (3) in the left detection region DL. The case where it occurred is shown. In FIG. 6, the detected capacitance value in the touch area T is indicated by a white circle (◯) in the leftmost graph.

  As shown in FIG. 6, the first to sixth left row detection lines WyL (1) to WyL (6) corresponding to the left detection region DL and the first to sixth right row detection wires WyR corresponding to the right detection region DR. Between (1) and WyR (6), a coupling capacity (hereinafter sometimes referred to as “coupling capacity”) Ccy is generated in each divided portion. It is desirable to make the width of the divided portion as small as possible so that the divided portion is not visually recognized by the user. However, the coupling capacitance Ccy tends to increase as the width of the divided portion decreases.

  In FIG. 6, scanning of the first to sixth left row detection wirings WyL (1) to WyL (6) corresponding to the left detection region DL (hereinafter sometimes referred to as “scan”) corresponds to the right detection region DR. The case where the scans of the first to sixth right row detection wirings WyR (1) to WyR (6) are sequentially performed in parallel by the row detection wirings 7a and 7b facing each other in the dividing unit is shown. Specifically, arbitrary row detection wirings 7a and 7b, for example, the jth (j is a natural number) th left row detection wiring WyL (j) and the jth right row detection wiring WyR (j) are sequentially parallel. And scanned. Hereinafter, the jth left row detection wiring may be referred to as “jth left row detection wiring”, and the jth right row detection wiring may be referred to as “jth right row detection wiring”.

  For example, the row detection wirings in the left detection region DL are the first left row detection wiring WyL (1), the second left row detection wiring WyL (2),..., The fifth left row detection wiring WyL (5), the sixth. Scanning is performed in the order of the left row detection wiring WyL (6). On the other hand, the row detection wiring in the right detection region DR is the same as the row detection wiring 7b in the left detection region DL, the first right row detection wiring WyR (1), the second right row detection wiring WyR (2),. The fifth right row detection wiring WyR (5) and the sixth right row detection wiring WyR (6) are scanned in this order.

  When the left detection region DL and the right detection region DR are sequentially scanned in this way, the third left row detection wiring WyL (left detection region DL) detected by the left capacitance detection circuit (L) 22a ( 3) and the capacitance detection value of the third right-row detection wiring WyR (3) in the right detection region DR scanned in parallel with the capacitance detection value formed between the touch region T ( Hereinafter, it may also be referred to as “false detection value”).

  FIG. 7 is an equivalent circuit diagram showing an equivalent circuit of the left detection region DL and the right detection region DR when the touch capacitance is formed on the touch screen 1. As shown in FIG. 7, for example, when a touch area T is generated in the jth left row detection wiring WyL (j) of the left detection region DL by touching an indicator, the jth left row detection wiring WyL (j) is touched. Two resistance elements Rwa and Rwb, that is, a first resistance element Rwa and a second resistance element Rwb are provided across the region T. At this time, a capacitance Ct (hereinafter also referred to as “touch capacitance”) Ct is formed between the touch region T and the jth left row detection wiring WyL (j). When the j-th left row detection wiring WyL (j) is scanned, the first resistance element Rwa detects the left capacitance via the corresponding selector circuit 27 of the left-row wiring switch circuit Y (L) 21a. It is connected to the detection end 26a of the circuit (L) 22a.

  Further, the j-th right-row detection wiring WyR (j) in the right detection region DR includes one resistance element (hereinafter also referred to as “third resistance element”) Rw. The j-th right-row detection wiring WyR (j) is scanned in parallel with the j-th left-row detection wiring WyL (j), and the third resistance element Rw becomes the corresponding selector of the right-row wiring switch circuit Y (R). The circuit 27 is connected to the detection end 26b of the right capacitance detection circuit (R) 22b. The jth left row detection wiring WyL (j) in the left detection region DL and the jth right row detection wiring WyR (j) in the right detection region DR are between the second resistance element Rwb and the third resistance element Rw. They are connected via a coupling capacitor Ccy that is formed. In FIG. 7, the left and right buffer circuits 25a and 25b are not shown for easy understanding.

  As shown in FIG. 7, the touch capacitance Ct includes the jth left row detection wiring WyL (j) in the left detection region DL and the jth right row detection wiring WyR (j in the right detection region DR that is scanned in parallel therewith. ) To the j-th right-row detection wiring WyR (j) through the coupling capacitance Ccy. This is detected by the right capacitance detection circuit (R) 22b via the corresponding selector circuit 27 of the right row wiring switch circuit Y (R) 21b, and generates a false detection value FV as shown in FIG. Let

  As described above, the touch capacitance detected through the jth right row detection wiring WyR (j) in the right detection region DR is the original touch capacitance Ct formed in the left detection region DL and the coupling capacitance Ccy. It becomes a series composite capacity. Therefore, if the coupling capacitance Ccy is extremely small with respect to the touch capacitance Ct, the series composite capacitance is only approximately equal to the coupling capacitance Ccy. However, when the coupling capacitance Ccy cannot be ignored with respect to the original touch capacitance Ct, the series composite capacitance approaches the touch capacitance Ct.

  In order to ensure the robustness of the touch screen 1 by increasing the thickness of the glass substrate constituting the base substrate 12 of the touch screen 1 or by further providing a protective glass on the front surface of the touch screen 1, an instruction is provided. The distance between the body and the detection wiring increases, and the touch capacitance Ct decreases. When the touch capacitance Ct is thus reduced, the coupling capacitance Ccy for the touch capacitance Ct cannot be ignored.

  As described above, when the left row detection wiring 7a and the right row detection wiring 7b that are opposed to each other in the divided portion of the left detection region DL and the right detection region DR are detected in parallel, either the left or right detection region is detected. Even when the touch capacitance Ct is formed in the row detection wiring 7, a false detection value appears as if the touch capacitance Ct was also formed in the row detection wiring 7 in the other detection region. In other words, crosstalk occurs in one of the left and right detection systems, that is, the left row detection wiring 7a and the right row detection wiring 7b from the other via the coupling capacitance Ccy of the left and right detection wirings. It can also occur. As described above, when detection operations corresponding to the left detection region DL and the right detection region DR are performed in parallel, detection system interference occurs.

  Using such a detection result, as shown in FIG. 4, the touch coordinate value is calculated by the touch coordinate calculation circuit 23 at the subsequent stage of the left capacitance detection circuit (L) 22a and the right capacitance detection circuit (R) 22b. When calculated, the false detection value described above may cause an erroneous determination as to whether or not a touch has occurred. For example, as an example of erroneous determination, when another touch occurs in the detection region where the false detection value appears, it is difficult to determine which of the touch capacitance Ct detection value and the false detection value is correct. Or it may be determined as if another touch has occurred at a position corresponding to the false detection value in the detection area. Therefore, it is not desirable that a false detection value is generated. Therefore, in this embodiment, the following configuration is adopted.

  FIG. 8 is a diagram schematically illustrating the scan order of the row detection wiring 7 in the touch panel according to the first embodiment of the present invention. In FIG. 8, as in FIG. 6, the indicator touches near the center of the intersection of the third left column detection wiring WxL (3) and the third left row detection wiring WyL (3) in the left detection region DL. Shows a case where the touch region T is generated. In the present embodiment, as shown in FIG. 8, the scan order of the row detection wiring 7a in the left detection region DL is shifted from the scan order of the row detection wiring 7b in the right detection region DR. That is, the scan is offset. In FIG. 8, for example, the row detection wiring 7a in the left detection region DL includes a first left row detection wiring WyL (1), a second left row detection wiring WyL (2),..., A fifth left row detection wiring Wy. (5) Scan in the order of the sixth left row detection wiring WyL (6). On the other hand, the row detection wiring 7b in the right detection region DR includes the fourth right row detection wiring WyR (4), the fifth right row detection wiring WyR (5), the sixth right row detection wiring WyR (6), and the first right row. Scanning is performed in the order of the detection wiring WyR (1), the second right-row detection wiring WyR (2), and the third right-row detection wiring WyR (3).

  As described above, in the present embodiment, by shifting the scanning order, two row detection wirings 7a and 7b that are adjacent to each other at the divided portions of the left detection region DL and the right detection region DR, for example, the jth left row detection wiring. The selector circuit 27 selects WyL (j) and the j-th right row detection wiring WyR (j) at different timings. That is, the electrostatic capacitance by the two adjacent row detection wirings 7a and 7b facing each other in the division unit is prevented from being detected simultaneously. Thus, unlike the case shown in FIG. 6, it is possible to prevent the false detection value from appearing in the right detection region DR as shown in FIG. That is, in the present embodiment, it is possible to prevent a false detection value from appearing, and thus it is possible to prevent erroneous determination of whether or not a touch has occurred.

  A shift amount between the scan order in the left detection region DL and the scan order in the right detection region DR of the row detection wiring 7 is referred to as a “scan offset amount”. For example, in the example shown in FIG. 8, the scan offset amount of the right detection region DR with respect to the left detection region DL in the row detection wiring 7 is “3”. This scan offset amount is an example and is not limited to this.

  FIG. 9 is an equivalent circuit diagram showing an equivalent circuit of the left detection region DL and the right detection region DR when the touch capacitance is formed on the touch screen 1 according to the first embodiment of the present invention. Similarly to the case shown in FIG. 7 described above, for example, when a touch region T occurs in the jth left row detection wiring WyL (j) of the left detection region DL, the jth left row detection wiring WyL (j) Two resistance elements Rwa and Rwb, that is, a first resistance element Rwa and a second resistance element Rwb are provided across T. At this time, an electrostatic capacitance, that is, a touch capacitance Ct is formed between the touch region T and the j-th left row detection wiring WyL (j). When the j-th left row detection wiring WyL (j) is scanned, the first resistance element Rwa detects the left capacitance via the corresponding selector circuit 27 of the left-row wiring switch circuit Y (L) 21a. It is connected to the detection end 26a of the circuit (L) 22a.

  The kth (k is a natural number) left row detection wiring (hereinafter sometimes referred to as “kth left row detection wiring”) WyL (k) of the left detection region DL is one resistance element (hereinafter “fourth resistance element”). Rw) will be provided. When the k-th left-row detection wiring WyL (k) is scanned, the fourth resistance element Rw passes through the selector circuit 27 corresponding to the left-row wiring switch circuit Y (L) 21a and the left capacitance detection circuit ( L) Connected to the detection end 26a of 22a.

  The j-th right-row detection wiring WyR (j) in the right detection region DR includes one resistance element, that is, the third resistance element Rw, as in the case illustrated in FIG. When the j-th right-row detection wiring WyR (j) is scanned, the third resistance element Rw passes through the selector circuit 27 corresponding to the right-row wiring switch circuit Y (R) and the right electrostatic capacitance detection circuit (R ) It is connected to the detection end 26b of 22b.

  The k-th (k is a natural number) right-row detection wiring (hereinafter sometimes referred to as “k-th right-row detection wiring”) WyR (k) of the right detection region DR is a single resistance element (hereinafter “fifth resistance element”). Rw). When the k-th right-row detection wiring WyR (k) is scanned, the fifth resistance element Rw passes through the selector circuit 27 corresponding to the right-row wiring switch circuit Y (R) 21b and the right capacitance detection circuit ( R) connected to the detection end 26b of 22b.

  The jth left row detection wiring WyL (j) in the left detection region DL and the jth right row detection wiring WyR (j) in the right detection region DR are between the second resistance element Rwb and the third resistance element Rw. They are connected via a coupling capacitor Ccy that is formed. The kth left row detection wiring WyL (k) in the left detection region DL and the kth right row detection wiring WyR (k) in the right detection region DR are between the fourth resistance element Rw and the fifth resistance element Rw. Are connected via a coupling capacitor Ccy.

  In the present embodiment, for example, as shown in FIG. 9, when the jth left row detection wiring WyL (j) in the left detection region DL is scanned, the kth right row detection wiring WyR (k) in the right detection region DR. ) Is scanned. At this time, the fifth resistance element Rw of the k-th right-row detection wiring WyR (k) is connected to the right-side capacitance detection circuit (R) via the corresponding selector circuit 27 of the right-row wiring switch circuit Y (R) 21b. 22b is connected to the detection end 26b.

  On the other hand, when the j-th left row detection wiring WyL (j) in the left detection region DL is scanned, the j-th right row of the right detection region DR that is adjacent to each other at the divided portion of the left detection region DL and the right detection region DR. In the detection wiring WyR (j), the detection voltage at the detection end 26b of the right capacitance detection circuit (R) 22b is supplied to the right buffer circuit 25b and the corresponding selector circuit 27 of the right row wiring switch circuit Y (R) 21b. Applied.

  Similarly, when the jth right row detection wiring WyR (j) of the right detection region DR is scanned in parallel with the jth left row detection wiring WyL (j) of the left detection region DL, the jth of the left detection region DL is scanned. In the left row detection wiring WyL (j), the detection voltage of the detection end 26a of the left capacitance detection circuit (L) 22a is the selector circuit 27 corresponding to the left buffer circuit 25a and the left row wiring switch circuit Y (L) 21a. Applied.

  FIG. 10 and FIG. 11 are timing charts showing the scan sequence of the detection wiring in the first embodiment of the present invention. FIG. 10 is a timing chart showing a detection wiring scan sequence in the left detection region DL, and FIG. 11 is a timing chart showing a detection wiring scan sequence in the right detection region DR.

  In this embodiment, as shown in FIG. 10, the left row wiring switch circuit Y (L) 21a causes the left row detection wiring 7a in the left detection region DL to be the first left row detection wiring WyL (1), the second The left-row detection wiring WyL (2),..., The fifth left-row detection wiring WyL (5), the sixth left-row detection wiring WyL (6) are scanned in this order, and the left capacitance detection circuit (L ) Connected to 22a and the capacitance is detected.

  In parallel with this, the right row detection wiring 7b in the right detection region DR is scanned. At this time, as shown in FIG. 11, the right row detection wiring 7b in the right detection region DR is offset from the left detection region DL, and the fourth right row detection wiring WyR (4) and the fifth right row detection wiring WyR. (5),..., Second right-row detection wiring WyR (2), third right-row detection wiring WyR (3) are scanned in this order and connected to the right capacitance detection circuit (R) 22b as a detection target. The capacitance is detected.

  In this way, after the row detection wirings 7a and 7b in the left and right detection areas DL and DR are scanned and detected in parallel, the column detection wirings 6a and 6b in the left and right detection areas DL and DR are scanned and detected in parallel. Move to the operation.

  FIG. 12 is a diagram for explaining the coupling capacitance Ccx between the column detection wirings 6a and 6b in the divided portion of the left detection region DL and the right detection region DR of the touch screen 1. First to sixth left row detection lines WyL (1) to WyL (6) corresponding to the left detection region DL, and first to sixth right row detection lines WyR (1) to WyR () corresponding to the right detection region DR. 6), a coupling capacitance Ccy is generated in each divided portion as shown in FIG. Similarly, also in the column detection wirings 6a and 6b, as shown in FIG. 12, in the divided portions, the column detection adjacent to each other along the longitudinal direction that is the extending direction of the divided portions, that is, adjacent to each other in the divided portions. A coupling capacitance Ccx is generated between the wirings 6a and 6b. In the present embodiment, a coupling capacitor Ccx is generated between the fourth left column detection wiring WxL (4) and the first right column detection wiring WxR (1).

  As shown in FIG. 12, for example, when a touch area T is generated near the center of the intersection of the fourth left column detection wiring WxL (4) and the third left row detection wiring WyL (3) by the touch of the indicator. A touch capacitance that is an electrostatic capacitance is formed between the touch region T and the fourth left column detection wiring WxL (4). In this state, consider a case where the left column wiring switch circuit X (L) 20a and the right column wiring switch circuit X (R) 20b scan the column detection wirings 6a and 6b in the left detection region DL and the right detection region DR. In this case, for example, the fourth left column detection wiring WxL (4) in the left detection region DL and the first right column detection wiring WxR (1) in the right detection region DR are simultaneously selected as detection targets in parallel, Detection is performed by a capacitance detection circuit (L) 22a and a right capacitance detection circuit (R) 22b. At this time, the touch capacitance generated in the fourth left column detection wiring WxL (4) also appears when the first right column detection wiring WxR (1) is selected and detected, and the right capacitance detection circuit ( R) A false detection value is generated in 20b.

  Therefore, in the present embodiment, two column detection wirings that are adjacent to each other in the divided portion of the left detection region DL and the right detection region DR, that is, the fourth left column detection wiring WxL (4) and the first right column detection wiring. The selector circuit 27 selects WxR (1) at different timings. That is, scanning is performed so that two row detection wirings 7a and 7b that face each other at the dividing portion and are not simultaneously selected and detected in parallel. In the present embodiment, as shown in FIG. 10 described above, the left column wiring switch circuit X (L) 20a causes the column detection wiring 6a in the left detection region DL to be changed to the first left column detection wiring WxL (1), the second The left column detection wiring WxL (2), the third left column detection wiring WxL (3), and the fourth left column detection wiring WxL (4) are scanned and selected in this order. In parallel with this, as shown in FIG. 11 described above, the column detection wiring 6b in the right detection region DR includes the first right column detection wiring WxR (1), the second right column detection wiring WxR (2), the third Scanning is performed in the order of the right column detection wiring WxR (3) and the fourth right column detection wiring WxR (4).

  In this way, the fourth left column detection wiring WxL (4) and the first right column detection wiring WxR (1) are not selected at the same time. As a result, when a touch capacitance is generated in one of the fourth left column detection wiring WxL (4) and the first right column detection wiring WxR (1) adjacent to each other in the division unit, and it is selected and detected, It is possible to prevent the false detection value of the other column detection wiring 6 from being generated via the coupling capacitor Ccx.

  In this manner, the row detection wiring 7 and the column detection wiring 6 in the left detection area DL and the right detection area DR are all scanned and detected in parallel. In the touch coordinate calculation circuit 23, for example, whether the maximum value of the capacitance detection result of the row detection wiring 7 and the maximum value of the capacitance detection result of the column detection wiring 6 are equal to or greater than a predetermined threshold value. The presence / absence of a touch is determined based on whether or not it is present. When it is determined that there is a touch, for example, the touch coordinates are interpolated using also the detection result of the detection wiring adjacent to the maximum value and the detection wiring adjacent thereto, and the detected touch coordinate data is output to an external device (not shown). . Such a series of operations is repeated.

  As described above, in the present embodiment, the dividing unit is shifted by shifting the scan order of the row detection wiring 7a in the left detection region DL and the scan order of the row detection wiring 7b in the right detection region DR, that is, by offsetting the scan. The left and right row detection wirings 7a and 7b that are adjacent to each other are scanned so as not to be simultaneously selected in parallel. Therefore, when a touch capacitance is generated in the row detection wiring 7 in either one of the left and right detection regions, the coupling capacitance between the row detection wirings 7a and 7b in the left and right detection regions adjacent to each other in the divided portion is used. As a result of detecting the capacitance of the other row detection wiring 7, it is possible to prevent a false detection value from appearing.

  In the present embodiment, scanning is performed so that the left and right column detection wirings 6 adjacent to each other in the dividing unit are not simultaneously selected. Accordingly, in the divided portion, one column detection wiring 6 has a touch capacitance among the column detection wirings 6a and 6b of the left detection region DL and the right detection region DR which are adjacent to each other along the longitudinal direction which is the extending direction of the divided portion. When this occurs, as a result of detecting the capacitance of the other column detection wiring 6 through the coupling capacitance between the one column detection wiring 6 and the other adjacent column detection wiring 6 in the dividing unit, The detection value can be prevented from appearing.

  In the present embodiment, the output voltages of the corresponding buffer circuits 25a and 25b are applied to the non-selected detection wirings 6 and 7, respectively. As a result, the coupling capacitance formed between the detection wirings 6 and 7 selected as the detection target and the non-selection detection wirings 6 and 7 in the same detection region can be reduced. Detection sensitivity can be improved.

<Second Embodiment>
As described above, for example, when a relaxation oscillation circuit using an RC circuit including a measurement capacitance is used as the capacitance detection circuit, the left capacitance detection circuit (L) 22a and the right capacitance detection of the left and right detection systems. The oscillation of the circuit (R) 22b is asynchronous. Therefore, when the jth left row detection wiring WyL (j) in the left detection region DL is scanned, the detection voltage of the detection end 26b corresponding to the right detection region DR is the jth right of the right detection region DR adjacent to the division unit. Applied to the row detection wiring WyR (j) via the right buffer circuit 25b. The detection voltage of the detection end 26b corresponding to the right detection region DR is applied to the jth left row detection wiring WyL (j) of the left detection region DL via the coupling capacitor Ccy. When viewed from the detection of the left detection region DL, it appears as a voltage unrelated to detection, that is, noise.

  This also applies to the detection of the right detection region DR, and the detection voltage of the detection end 26a corresponding to the left detection region DL is applied via the left buffer circuit 25a, and this voltage relays the coupling capacitor Ccy. When viewed from the detection of the right detection region DR, it appears as noise. Such noise is called “coupling noise”.

  The magnitude of such coupling noise is, for example, the left row wiring switch circuit Y (L) 21a and the right row wiring switch circuit Y (R) 21b, the left capacitance detection circuit (L) 22a, and the right capacitance. It depends on the relationship between the capacitance such as the parasitic capacitance of the circuit such as the detection circuit (R) 22b and the coupling capacitance Cc. Although the amount of coupling noise can be reduced by increasing the former, it is not desirable in terms of detection time and detection sensitivity.

  In the first embodiment described above, as described with reference to FIG. 12, the coupling capacitance Ccx is generated between the column detection wirings 6 adjacent to each other in the dividing portion. Therefore, when scanning the fourth left column detection wiring WxL (4) in the left detection region DL, the detection voltage of the detection end 26a connected to the fourth left column detection wiring WxL (4) is adjacent in the dividing unit. It is applied to the first right column detection wiring WxR (1) in the right detection region DR, and appears as noise at the detection end 26b of the right capacitance detection circuit (R) 20b in the right detection region DR.

  Therefore, in the present embodiment, when the jth left row detection wiring WyL (j) in the left detection region DL is selected as a detection target, the jth right row detection wiring WyR (j) in the right detection region DR adjacent to the division unit. The voltage applied to is a fixed potential such as a ground potential. Similarly, when the k-th right row detection wiring WyR (k) in the right detection region DR is selected as a detection target, the applied voltage to the k-th left row detection wiring WyL (k) in the left detection region DL adjacent in the division unit. Is a fixed potential such as a ground potential. When each of the left detection region DL and the right detection region DR sequentially selects and detects the column detection wiring 6 as a detection target, the cross capacitance with the row detection wiring is reduced as in the first embodiment. For this purpose, the detection potentials of the detection ends 26a and 26b are applied via the left and right buffer circuits 25a and 25b.

  FIG. 13 is a diagram showing a configuration of the left column wiring switch circuit X (L) 20a according to the second embodiment of the present invention. The left row wiring switch circuit Y (L) 21a, the right row wiring switch circuit Y (R) 21b, and the right column wiring switch circuit X (R) 20b are the same as the left column wiring switch circuit X (L) 20a shown in FIG. Since it is the structure of this, description is abbreviate | omitted. Other configurations except the left column wiring switch circuit X (L) 20a, the left row wiring switch circuit Y (L) 21a, the right row wiring switch circuit Y (R) 21b, and the right column wiring switch circuit X (R) 20b are as follows: Since it is the same as that of the first embodiment, illustration and detailed description are omitted.

  The selector circuit 27 corresponding to the row detection wiring 7 selected as the detection target is switched to the first contact a side based on a command from the detection control circuit 24 as in the first embodiment. The left row wiring switch circuit Y (L) 21a is connected to the detection end of the left capacitance detection circuit (L) 22a, and the right row wiring switch circuit Y (R) 21b is connected to the right capacitance detection circuit (R). ) Connected to the detection end of 22b.

  The selector circuit 27 corresponding to the row detection wiring 7 other than the row detection wiring 7 selected as the detection target, that is, the non-selected row detection wiring 7 is switched to the second contact b side and selected by the 2-to-1 selector circuit 30. The applied potential is applied to the row detection wiring 7. The 2-to-1 selector circuit 30 is switched to the fourth contact d side when scanning and detecting the row detection wiring 7 based on a command from the detection control circuit 24. The 2-to-1 selector circuit 30 is switched to the third contact c side when the column detection wiring 6 is detected by scanning. Thus, in the left row wiring switch circuit Y (L) 21a, the output voltage of the left buffer circuit 25a is output to each second contact b side node of the selector circuit 27, and in the right row wiring switch circuit Y (R) 21b, The output voltage of the right buffer circuit 25 b is output to each second contact b side node of the selector circuit 27.

  That is, when the capacitance is detected by selecting the jth left row detection wiring WyL (j) in the left detection region DL, at least the jth right row detection wiring WyR (j) in the right detection region DR adjacent to the division unit. A fixed potential such as a ground potential is applied to. Further, when the k-th right-row detection wiring WyR (k) in the right detection region DR is selected and the capacitance is detected, at least the k-th left-row detection wiring WyL (k) in the left detection region DL adjacent to the division unit. A fixed potential such as a ground potential is applied to.

  When the column detection wiring 6 is selected and detected in both the left detection area DL and the right detection area DR, the row detection wiring 7a of the left detection area DL is connected to the detection end of the left capacitance detection circuit (L) 22a. A voltage obtained by buffering the detection voltage by the left buffer circuit 25a is applied. A voltage obtained by buffering the detection voltage at the detection end of the right capacitance detection circuit (R) 22b with the right buffer circuit 25b is applied to the row detection wiring 7b in the right detection region DR. As a result, as in the first embodiment, the cross capacitance of the row detection wiring 7 when the column detection wiring 6 is selected and detected can be reduced.

  14 and 15 are timing charts showing the scan sequence of the detection wiring in the second embodiment of the present invention. FIG. 14 is a timing chart showing a scan sequence of the detection wiring in the left detection region DL. FIG. 15 is a timing chart showing a scan sequence of the detection wiring in the right detection region DR.

  The scan sequence of the row detection wiring 7 and the column detection wiring 6 is the same as in the case of the first embodiment shown in FIGS. When scanning the row detection wiring 7 in the left and right detection regions DL and DR, the two-to-one selector circuit 30 of the left row wiring switch circuit Y (L) 21a and the right row wiring switch circuit Y (R) 21b is shown in FIG. 13 is switched to the fourth contact d side, and a fixed potential such as a ground potential is applied to the second contact b side of the selector circuit 27. Therefore, a fixed potential is applied to the non-selected row detection wiring 7 when scanning the row detection wiring 7.

  As a result, when the row detection wiring 7 having one of the left and right detection areas DL and DR is selected and detected, the row detection wiring 7 and the other adjacent to each other at the dividing portion are detected. It is possible to prevent the voltage obtained by buffering the detection voltage of the other detection region from being mixed as noise through the coupling capacitance Ccy with the row detection wiring 7 in the detection region.

  The two-to-one selector circuit 30 of the left row wiring switch circuit Y (L) 21a and the right row wiring switch circuit Y (R) 21b is switched to the third contact c side in FIG. The detection voltage at the detection end of (L) 22a and the right capacitance detection circuit (R) 22b is applied to the column detection wiring 6 via the left buffer circuit 25a and the right buffer circuit 25b, respectively. As a result, the cross section capacitance with the row detection wiring 7 when the column detection wiring 6 is detected by scanning can be reduced, and the detection sensitivity can be improved.

  When scanning the column detection wiring 6, as in the first embodiment, the fourth left column detection wiring WxL (4) and the first right column detection wiring WxR (1) adjacent to each other in the dividing unit are parallel to each other. Scan to avoid selecting and detecting at the same time. As a result, when a touch capacitance is generated in one of the fourth left column detection wiring WxL (4) and the first right column detection wiring WxR (1) adjacent to each other in the division unit, and it is selected and detected, It is possible to prevent the false detection value of the other column detection wiring 6 from being generated via the coupling capacitor Ccx.

  At this time, the two-to-one selector circuit 30 of the left column wiring switch circuit X (L) 20a and the right column wiring switch circuit X (R) 20b is switched to the fourth contact d side in FIG. A fixed potential such as a ground potential is applied to the second contact b side. Therefore, a fixed potential is applied to the non-selected column detection wiring 6 when scanning the column detection wiring 6.

  As a result, when the column detection wiring 6 having one of the left and right detection areas DL and DR is selected and detected, the column detection wiring 6 and the other detection area adjacent to each other at the dividing portion are detected. A fixed potential is applied to the column detection wiring 6. Therefore, it is possible to prevent a voltage obtained by buffering the detection voltage of the other detection region from being mixed as noise through the coupling capacitor Ccx.

  During scanning of the column detection wiring 6, the 2-to-1 selector circuit 30 of the left row wiring switch circuit Y (L) 21a and the right row wiring switch circuit Y (R) 21b is switched to the third contact c side in FIG. The detection voltages at the detection ends of the left capacitance detection circuit (L) 22a and the right capacitance detection circuit (R) 22b are applied to the row detection wiring 7 via the left buffer circuit 25a and the right buffer circuit 25b, respectively. Is done. As a result, the cross section capacitance with the row detection wiring 7 when the column detection wiring 6 is detected by scanning can be reduced, and the detection sensitivity can be improved.

<Third Embodiment>
The length of the adjacent portion between the column detection wirings 6 adjacent to each other in the dividing portion is substantially equivalent to the length of the column detection wiring 6 although it depends on the number of row detection wirings 7. On the other hand, the opposing length between adjacent row detection wires 7 in the divided portion corresponds to the width of the row detection wires 7, in other words, the pitch of the row detection wires 7. Therefore, the length of the adjacent portion between the column detection wirings 6 is several tens of times the opposing length between the row detection wirings 7, so that the coupling capacitance Ccx between the adjacent column detection wirings 6 is equal to the adjacent row. The coupling capacitance Ccy between the detection wirings 7 is considerably large. Further, since the column detection wiring 6 adjacent in the divided portion is also close to all the row detection wirings 7 in the other detection region, a coupling capacitance Ccxy with these detection wirings is further added.

  In the above-described embodiment, the coupling capacitance between the column detection wirings 6 in the same detection region and the cross capacitance between the column detection wiring 6 and the row detection wiring 7 are the non-selected wirings based on the potential buffered with the detection voltage. The configuration is such that it is canceled by applying to the. Therefore, the influence on the detection of the selected column detection wiring 6 is extremely small.

  However, the coupling capacitance between the column detection wiring 6 in one detection region of the dividing unit and the column detection wiring 6 in the other detection region is that the other detection voltage is buffered in the first embodiment. The potential becomes a fixed potential in the second embodiment described above. Therefore, as compared with the other column detection wirings 6, the parasitic capacitance becomes extremely large, and the detection sensitivity may be lowered due to the influence. Therefore, in the present embodiment, the following configuration is adopted.

  FIG. 16 is a diagram showing a configuration of the left column wiring switch circuit X (L) 20a according to the third embodiment of the present invention. FIG. 17 is a diagram showing a configuration of the right column wiring switch circuit X (R) 20b according to the third embodiment of the present invention. In the present embodiment, the left column wiring switch circuit X (L) 20a and the right column wiring switch circuit X (R) 20b each include a 3-to-1 selector circuit 31.

  The left row wiring switch circuit Y (L) 21a has the same configuration as the left column wiring switch circuit X (L) 20a shown in FIG. The right row wiring switch circuit Y (R) 21b has the same configuration as the right column wiring switch circuit X (R) 20b shown in FIG. Other configurations except the left column wiring switch circuit X (L) 20a, the left row wiring switch circuit Y (L) 21a, the right row wiring switch circuit Y (R) 21b, and the right column wiring switch circuit X (R) 20b are as follows: Since it is the same as that of the first embodiment, illustration and detailed description are omitted.

  In the case of the left detection region DL, the left row wiring switch circuit Y (L) 21a and the right row wiring switch circuit Y (R) 21b in the second embodiment described above have the output potential and the fixed potential of the left buffer circuit 25a. The second contact b side node of the selector circuit 27 is selected and supplied to the second contact b side node of the selector circuit 27. In the case of the right detection region DR, the output potential and the fixed potential of the right buffer circuit 25b are selected. 2 to 1 selector circuit 30 is provided.

  On the other hand, each switch circuit 20a, 20b, 21a, 21b of the present embodiment selects a three-to-one selector circuit 31 that selectively supplies the output potential and fixed potential of the left buffer circuit 25a and right buffer circuit 25b. It is configured with. Other configurations are the same as those of the first embodiment described above, and thus detailed description thereof is omitted.

  18 and 19 are timing charts showing a scan sequence of the detection wiring in the touch panel according to the third embodiment of the present invention. FIG. 18 is a timing chart showing a detection wiring scan sequence in the left detection area DL, and FIG. 19 is a timing chart showing a detection wiring scan sequence in the right detection area DR.

  Scanning and detection of the row detection wiring 7 in each of the left and right detection regions DL and DR are the same as in the second embodiment described above, and the left row wiring switch circuit Y (L) 21a corresponding to the detection target wiring and the right The selector circuit 27 of the row wiring switch circuit Y (R) 21b is sequentially switched to the first contact a side and selected, and when not selected, the selector circuit 27 is switched to the second contact b side in FIGS. The 3-to-1 selector 31 that selects the supply potential to the node on the second contact b side of the selector circuit 27 is switched to the fourth contact d side in FIGS. 16 and 17, and a fixed potential such as a ground potential is applied. In addition, the selector circuit 27 of the left column wiring switch circuit X (L) 20a and the right column wiring switch circuit X (R) 20b is switched to the second contact b side in FIGS. 16 and 17, and a three-to-one selector circuit. 31 is switched to the third contact c side.

  In this way, the row detection wirings 7 in the left and right detection regions DL and DR are scanned and detected in parallel, and then the column detection wiring 6 is scanned and detected. In the first and second embodiments described above, all the row detection wirings 7 and the column detection wirings 6 are configured to be scanned and detected in parallel. Only scanning and detection of the column detection wirings in the left and right detection areas DL and DR are performed independently in the left and right detection areas DL and DR.

  That is, first, the first right column detection wiring WxR (1) in the right detection region DR in the divided portion is scanned and detected independently. At this time, the selector circuit 27 corresponding to the first right column detection wiring WxR (1) of the right column wiring switch circuit X (R) 20b is switched to the first contact a side in FIG. 16 and FIG. The column detection wiring WxR (1) is selected and connected to the detection end of the right capacitance detection circuit (R) 22b as a detection target wiring. During the scan and detection period of the column detection wiring 6 in the right detection region, the 3: 1 selector circuit 31 of the right column wiring switch circuit X (R) 20b is switched to the fourth contact d side in FIGS. As in the second embodiment, a fixed potential is applied to the non-selected column detection wiring 6. Further, the 3: 1 selector circuit 31 of the right row wiring switch circuit Y (R) 21b is switched to the third contact c side, and all row detections in the right detection region DR are detected as in the second embodiment. The potential at the detection end of the right capacitance detection circuit (R) 22b is applied to the wiring 7 via the right buffer circuit 25b, and the cross section capacitance with the column detection wiring 6 is reduced.

  When the first right column detection wiring WxR (1) in the right detection region DR is scanned and detected alone, scanning and detection are not performed in the left detection region DL. That is, all the selector circuits 27 of the left column wiring switch circuit X (L) 20a and the left row wiring switch circuit Y (L) 21a are switched to the second contact b side in FIG. 16 and FIG. Do not select as detection target. At this time, the 3-to-1 selector circuit 31 that selects the potential to be supplied to the second contact b side node is switched to the fifth contact e side, and the detection of the first right column detection wiring WxR (1) in the right detection region DR. Sometimes, the detection potential at the detection end of the right capacitance detection circuit (R) 22b is applied via the right buffer circuit 25b. This can reduce the parasitic capacitance between the first right column detection wiring WxR (1) in the right detection region DR and the fourth left column detection wiring WxL (4) in the left detection region DL in the division unit. Therefore, a decrease in detection sensitivity can be prevented.

  After scanning and detecting the first right column detection wiring WxR (1) in the right detection region DR alone, the column detection wiring 6 that is not in the division unit is arranged in parallel as in the first and second embodiments. Scan and detect sequentially.

  Then, the fourth left column detection wiring WxL (4) in the left detection region DL in the division unit is scanned and detected alone. At this time, the selector circuit 27 corresponding to the fourth left column detection wiring WxL (4) of the left column wiring switch circuit X (L) 20a is switched to the first contact a side in FIGS. The column detection wiring WxL (4) is selected and connected to the detection end of the left capacitance detection circuit (L) 22a as a detection target wiring. During the scan and detection period of the column detection wiring 6 in the left detection region DL, the 3: 1 selector circuit 31 of the left column wiring switch circuit X (L) 20a is switched to the fourth contact d side in FIGS. As in the second embodiment, a fixed potential is applied to the non-selected column detection wiring 6. Further, the 3: 1 selector circuit 31 of the left row wiring switch circuit Y (L) 21a is switched to the third contact c side, and all row detections in the left detection area DL are detected as in the second embodiment. The detection end potential of the left capacitance detection circuit (L) 22a is applied to the wiring 7 via the left buffer circuit 25a, and the cross section capacitance with the column detection wiring is reduced.

  When the fourth left column detection wiring WxL (4) in the left detection region DL is scanned and detected alone, scanning and detection are not performed in the right detection region DR. That is, all the selector circuits 27 of the right column wiring switch circuit X (R) 20b and the right row wiring switch circuit Y (R) 21b are switched to the second contact b side in FIGS. Do not select as detection target. At this time, the 3-to-1 selector circuit 31 that selects the potential to be supplied to the second contact b side node is switched to the fifth contact e side, and when the fourth column detection wiring WxL (4) in the left detection region DL is detected. The detection potential at the detection end of the left capacitance detection circuit (L) 22a is applied via the left buffer circuit 25a. This can reduce the parasitic capacitance between the fourth column detection wiring WxL (4) in the left detection region DL and the first right column detection wiring WxR (1) in the right detection region DR in the division unit. Therefore, a decrease in detection sensitivity can be prevented.

<Fourth embodiment>
In the present embodiment, a liquid crystal display device in which a touch panel and a liquid crystal display panel are integrally formed by bonding the touch screen 1 in the first embodiment to the liquid crystal display panel 41 will be described.

  FIG. 20 is a cross-sectional view showing a configuration of a liquid crystal display device according to the fourth embodiment of the present invention. The liquid crystal display device includes a touch panel 100 including the touch screen 1 shown in FIG. 3 described above, a liquid crystal display panel 41, and a backlight 49. The liquid crystal display panel 41 includes a color filter substrate 44, a TFT array substrate 46, a liquid crystal layer 45, an adhesive layer 47, and a polarizing plate 48. In FIG. 20, the description of the FPC board 17 and the controller board 18 shown in FIG. 3 is omitted for easy understanding.

  The color filter substrate 44 is formed by forming a color filter, a black matrix, a transparent electrode, and an alignment film on a glass substrate. The TFT array substrate 46 is formed by forming a thin film transistor (abbreviation: TFT) as a switching element on a glass substrate. The liquid crystal layer 45 is sandwiched between the color filter substrate 44 and the TFT array substrate 46, and is made of, for example, twisted nematic (abbreviation: TN) liquid crystal. The polarizing plate 48 is adhered to the surface on the other side in the thickness direction of the TFT array substrate 46 by the adhesive layer 47. Further, a polarizing plate 42 is adhered to the surface on one side in the thickness direction of the color filter substrate 44 by an adhesive layer 43. A backlight 49 as a light source is disposed on the other side in the thickness direction, which is the back side of the liquid crystal display panel 41.

  The touch screen 1 according to the first embodiment is adhered to the polarizing plate 42 disposed on one side in the thickness direction, which is the front side of the liquid crystal display panel 41, by the adhesive layer 40.

  A signal corresponding to an image to be displayed (hereinafter also referred to as “image signal”) is input to the TFT array substrate 46 from an external driver circuit (not shown). The TFT array substrate 46 changes the alignment direction of the liquid crystal molecules by controlling the voltage applied to the liquid crystal layer 45 via the switching elements formed by the TFTs formed for each pixel in accordance with the input image signal. Incident light from the backlight 49 passes through the polarizing plate 48 to become linearly polarized light, and passes through the liquid crystal layer 45 so that the vibration direction is bent according to the signal of the image to be displayed. The light whose vibration direction is bent passes through the color filter formed on the color filter substrate 44, and is separated into light of the three primary colors, and further passes through the polarizing plate 42 on the front side, so as to respond to the image signal. The light has a high light intensity. Further, the light that has passed through the polarizing plate 42 passes through the touch screen 1 on the front surface and is visually recognized by the user as display light.

  In this way, the liquid crystal display device performs a desired display by controlling the transmittance of light from the backlight 49 in accordance with the image signal. Further, the touch panel 100 including the touch screen 1 calculates the touch coordinate value based on the change in the oscillation cycle, and outputs the touch coordinate value as touch coordinate data, as in the first embodiment.

  As described above, the touch panel 100 prevents the false detection value from appearing by shifting the scanning order of the detection wirings 6 and 7 between the left detection region DL and the right detection region DR, and the presence or absence of occurrence of touch. The effect that a stable touch coordinate calculation result can be obtained without causing determination is achieved. By configuring the liquid crystal display device with such a touch panel 100, it is possible to realize a liquid crystal display device that can obtain a stable touch coordinate calculation result without erroneous determination of whether or not a touch has occurred.

  In the liquid crystal display device according to the present embodiment, the touch screen 1 is attached to the display panel 41 so as to be integrated with the liquid crystal display device. Therefore, the touch screen holding mechanism that has been conventionally required can be eliminated, and the entire device can be made thin. It becomes possible.

  Further, since the touch screen 1 and the display panel 41 are integrally formed, dust and the like are prevented from entering the gap between the touch screen 1 and the display panel 41, and adverse effects on the display caused by the dust and the like are prevented. be able to.

  Further, as described in the first embodiment, in the touch screen 1, the detection wiring groups 6 and 7 are configured by the plurality of detection wirings 2 and 3, and the detection wirings 2 and 3 are connected to each other. By setting the area of the slit-shaped opening large, a decrease in the transmittance of display light is suppressed. As a result, most of the light passing through the polarizing plate 42 passes through the touch screen 1 and becomes display light. Therefore, even if the touch screen 1 is disposed on the front surface of the liquid crystal display panel 41, the display luminance is hardly lowered.

  In each of the above-described embodiments, for the sake of convenience, the row detection wirings 7 in the left and right detection regions DL and DR have been described as six and the column detection wirings 6 as four. It is not limited to. Further, in each of the above-described embodiments, the scan offset amount of the row detection wiring 7 is described as “3”, that is, “shift by three”, but the adjacent row detection wirings 7 are selected in parallel by the division unit and detected. If not, the offset amount can be selected as appropriate.

  Further, the column detection wirings 6 in the left and right detection regions DL and DR have been described in the above-described embodiments in which scanning is sequentially performed from the left, but the column detection wirings 6 adjacent to each other in the division unit are parallel to each other. The scanning order is not limited to this as long as it is not selected and detected.

  In each of the above-described embodiments, the configuration in which the detection area of the touch screen 1 is divided into two in the left-right direction has been described. However, the detection area may be divided into two in the vertical direction, or may be divided into four in the vertical direction and the left-right direction. However, it can be similarly implemented.

  In each of the above-described embodiments, the left column wiring switch circuit X (L) 20a, the right column wiring switch circuit X (R) 20b, and the left row wiring switch circuit Y (L) 21a that select the detection wirings 6 and 7 are used. , And the right-row wiring switch circuit Y (R) 21b are the two-to-one selector circuit 27 or the two-to-one selector circuit 27 provided corresponding to the detection wirings 6 and 7, and the potential applied to the non-selected wiring. However, the present invention is not limited to such a structure. Left column wiring switch circuit X (L) 20a, right column wiring switch circuit X (R) 20b, left row wiring switch circuit Y (L) 21a, and right row wiring switch circuit Y ( R) 21b only needs to be configured to select the detection wirings 6 and 7 and connect them to the detection end of the capacitance detection circuit, and to switch the potential applied to the non-selection wiring.

  In addition, the detection method has been described centering on a method using a relaxation oscillation circuit in which the oscillation cycle changes according to a change in detection capacitance, but is not limited to such a detection method. For example, a method using a hysteresis oscillation circuit may be used.

  1 touch screen, 2 detection column wiring, 3 detection row wiring, 4 column connection wiring, 5 row connection wiring, 6 detection column wiring group, 7 detection row wiring group, 8, 9 lead wiring, 10 terminals , 12 base substrate, 13 interlayer insulating film, 14 protective film, 17 flexible printed circuit board (FPC), 18 controller substrate, 19 detection processing circuit, 20a left column wiring switch circuit X (L), 20b right column wiring switch circuit X ( R), 21a Left row wiring switch circuit Y (L), 21b Right row wiring switch circuit Y (R), 22a Left capacitance detection circuit (L), 22b Right capacitance detection circuit (R), 23 Touch coordinates Calculation circuit, 24 detection control circuit, 25a left buffer circuit, 25b right buffer circuit, 41 liquid crystal display panel, 100 touch panel, DL left detection area , DR right detection area.

Claims (7)

A touch screen having a plurality of detection areas divided by division sections extending in a predetermined row direction or column direction, each detection area having a plurality of detection wirings arranged in the row direction and the column direction; ,
A switch circuit for sequentially selecting the plurality of detection wirings in parallel in the plurality of detection regions;
A capacitance detection circuit for detecting a capacitance formed between the detection wiring selected by the switch circuit and an indicator close to the touch screen;
A touch coordinate calculation circuit that calculates touch coordinates representing the position of the indicator on the touch screen based on the detection result of the capacitance detection circuit;
The touch panel according to claim 1, wherein the switch circuit selects two detection wirings that are adjacent to each other with the terminal portions facing each other at different timings. A touch screen having a plurality of detection areas divided by division sections extending in a predetermined row direction or column direction, each detection area having a plurality of detection wirings arranged in the row direction and the column direction; ,
A switch circuit for sequentially selecting the plurality of detection wirings in parallel in the plurality of detection regions;
A capacitance detection circuit for detecting a capacitance formed between the detection wiring selected by the switch circuit and an indicator close to the touch screen;
A touch coordinate calculation circuit that calculates touch coordinates representing the position of the indicator on the touch screen based on the detection result of the capacitance detection circuit;
The touch panel according to claim 1, wherein the switch circuit selects two detection wirings adjacent to each other along an extending direction of the division unit at different timings. A plurality of capacitance detection circuits provided corresponding to each detection region;
A plurality of buffer circuits provided corresponding to each capacitance detection circuit and buffering and outputting a detection voltage appearing at a detection node of each capacitance detection circuit;
2. The output voltage of the buffer circuit is applied to a detection wiring other than the detection wiring selected by the switch circuit among the plurality of detection wirings in each detection region. 2. The touch panel according to 2. A plurality of capacitance detection circuits provided corresponding to each detection region;
A plurality of buffer circuits provided corresponding to each capacitance detection circuit and buffering and outputting a detection voltage appearing at a detection node of each capacitance detection circuit;
The switch circuit sequentially selects detection wirings arranged in the row direction among the plurality of detection wirings in each detection region, and then sequentially selects detection wirings arranged in the column direction. ,
When the detection wiring arranged in the row direction is sequentially selected by the switch circuit, the detection wiring other than the detection wiring selected by the switch circuit among the detection wirings arranged in the row direction is selected. A fixed potential is applied to the wiring, and the output voltage of the corresponding buffer circuit is applied to the detection wiring arranged in the column direction.
When the detection wiring arranged in the column direction is sequentially selected by the switch circuit, the detection wiring other than the detection wiring selected by the switch circuit among the detection wirings arranged in the column direction is selected. 3. The touch panel according to claim 1, wherein a fixed potential is applied to the wiring, and an output voltage of the corresponding buffer circuit is applied to the detection wiring arranged in the row direction. A plurality of capacitance detection circuits provided corresponding to each detection region;
A plurality of buffer circuits provided corresponding to each capacitance detection circuit and buffering and outputting a detection voltage appearing at a detection node of each capacitance detection circuit;
When one of the two detection wirings adjacent to each other along the extending direction of the divided portion is selected by the switch circuit, the other detection wiring is included. The touch panel according to claim 2, wherein an output voltage of the corresponding buffer circuit is applied to each detection wiring in the detection region. A touch panel according to any one of claims 1 to 5,
And a display panel mounted on the touch screen of the touch panel.   The display device according to claim 6, wherein the touch screen is adhesively fixed to a front side of the display panel.

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