JP4944975B2 - Touch panel device - Google Patents

Description

  The present invention relates to a capacitive touch panel device in which electrodes are arranged in a grid pattern and detects a touch position based on a change in an output signal of the electrode accompanying a change in capacitance according to a touch operation, in particular, a transmission electrode The present invention relates to a mutual capacitance type touch panel device that receives a charge / discharge current signal that flows through a receiving electrode in response to a drive signal to which is applied and detects a touch position based on the charge / discharge current signal.

  There are various types of touch panel devices that differ in the principle of detecting the touch position. However, in a configuration in which a large number of electrodes are arranged in a panel, such as a resistive film type or a capacitance type, the electrodes are used as antennas. Because of this, it becomes easy to be affected by external noise. In particular, in the capacitance method, noise is detected by detecting the touch position using a minute change in capacitance near the electrode due to the approach or contact of a conductive object (for example, a human body). Therefore, effective noise countermeasures are desired.

  As a countermeasure against noise related to such a touch panel device, conventionally, in a capacitive touch panel device, a technique for removing noise caused by a display device used in combination with the touch panel device is known (see Patent Documents 1 and 2). ). In addition, in a capacitive touch panel device, a technique for preventing the influence of noise entering from the outside with a shield wire is known (see Patent Document 3). In addition, in a resistive film type touch panel device, a technique for removing induced noise caused by an induced voltage caused by an operator's finger is known (see Patent Document 4).

JP 63-174120 A JP 2010-009439 A JP 2009-237673 A JP-A-2-176922

  By the way, touch panel devices are widely used in the field of personal computers and personal digital assistants, but this touch panel device can be used in presentations and lectures for a large number of people by combining it with a large screen display device. It can be used as a so-called interactive whiteboard. In this case, if a touch panel device adopts a capacitance method, particularly a mutual capacitance method, a plurality of touch positions are detected simultaneously, so-called multi-touch (multi-inspection) The convenience can be improved.

  However, in the mutual capacitance method, since the touch position is detected by a minute current flowing through the receiving electrode, the impedance on the receiving side is high and originally susceptible to external noise, but when the touch panel device becomes larger, the electrode becomes longer This makes it more susceptible to external noise.

  In particular, the leader line connecting the transmission substrate and the transmission electrode that generates the drive signal to be applied to the transmission electrode becomes longer as the touch panel device becomes larger, and in order to reduce the number of transmission substrates, a small number of transmission substrates are used. When the leader lines are arranged so that the leader lines gather together, the angle of the leader lines becomes almost parallel to the receiving electrode. For this reason, the receiving electrode is easily affected by the inductive action caused by the current due to the drive signal applied to the transmitting electrode flowing in the lead wire, and a large induction noise is generated. The conventional noise countermeasure described above is not an effective solution for the induced noise generated in the receiving electrode due to the lead wire of the transmitting electrode.

  In addition, the length of the leader line varies depending on the positional relationship between the transmission electrode and the transmission board. The longer the distance between the transmission electrode and the transmission board, the longer the leader line, and the length of the leader line becomes longer. Inductive noise increases in response to this. For this reason, the magnitude of the induction noise differs depending on the position, and there is a problem that the sensitivity for detecting the touch position varies greatly.

  The present invention has been devised to solve such problems of the prior art, and its main purpose is caused by the inductive action caused by the current caused by the drive signal applied to the transmission electrode flowing in the lead wire. An object of the present invention is to provide a touch panel device configured to reduce induction noise generated in a receiving electrode. Furthermore, the present invention can reduce variations in the sensitivity of touch position detection caused by the magnitude of the induced noise generated in the receiving electrode depending on the length of the lead line connecting the transmitting electrode and the transmitting substrate. It is another object of the present invention to provide a touch panel device configured to be able to.

The touch panel device of the present invention includes a panel body in which a plurality of transmission electrodes that are parallel to each other and a plurality of reception electrodes that are parallel to each other are arranged in a grid, a transmission unit that applies a drive signal to the transmission electrodes, A receiving unit that receives a charge / discharge current signal of the receiving electrode in response to a drive signal applied to the transmitting electrode and outputs a level signal for each electrode intersection, and a substantially radial shape between the transmitting unit and the transmitting electrode The panel body has a touch surface on which the transmission electrode and the reception electrode are formed. A front plate disposed on the front side of the transmitter and a rear plate formed of a conductive material and disposed on the rear side of the transmission electrode and the reception electrode, and the transmitter is fixed to the rear plate. And the drawer is The transmitter unit has a region in which at least a part of the lead-out portion that is folded back from the front side to the back side of the panel body in parallel with the parallel running direction of the receiving electrode and is substantially radially formed is close to the back plate. The configuration is connected to

According to the present invention, the longer the overall length of the lead wire and the greater the induction noise generated in the reception electrode, the longer the portion along the conductive back plate, and the induction noise can be reduced. Noise can be made small and uniform, thereby reducing variations in sensitivity of touch position detection .

Overall configuration diagram showing a touch panel device according to the present invention Schematic configuration diagram of the transmission unit shown in FIG. Schematic configuration diagram of the receiver shown in FIG. Schematic configuration diagram of the received signal processing unit shown in FIG. The top view which shows the electrode sheet which comprises the panel main body shown in FIG. Sectional view of the panel body shown in FIG. Rear view of the panel body shown in FIG. The top view which shows the transmission side drawer | drawing-out part of the electrode sheet shown in FIG. 5 in detail The top view which shows the receiving side drawer | drawing-out part of the electrode sheet shown in FIG. 5 in detail Schematic plan view showing a wiring pattern and a modification of the transmission side lead-out portion of the electrode sheet shown in FIG. The figure which shows the difference in the dispersion | variation degree of the receiving sensitivity by the difference in the separation distance of a transmission side drawer | drawing-out part and a backplate. The figure which shows the effect which improves the variation degree of reception sensitivity by making the outgoing line of the transmission side close to the backplate in a plane Typical sectional drawing which shows the modification of the panel main body shown in FIG. Typical sectional drawing which shows the modification of the panel main body shown in FIG.

A first invention made to solve the above problems is a panel body in which a plurality of transmitting electrodes that run in parallel with each other and a plurality of receiving electrodes that run in parallel with each other are arranged in a grid pattern, and driven with respect to the transmitting electrodes A transmission unit that applies a signal, a reception unit that receives a charge / discharge current signal of the reception electrode in response to a drive signal applied to the transmission electrode, and outputs a level signal for each electrode intersection; the transmission unit; The panel body has a touch surface formed thereon, and the panel body is formed in a substantially radial shape with respect to the transmission electrode and provided with a lead line so as to gather from one end side toward the other end side. the has a surface plate disposed on the front side of the transmission electrode and the reception electrode, and a back plate arranged on the rear side of the transmission electrode and the reception electrode is formed of a conductive material Te, the transmission unit Is fixed to the back plate and The drawer part is folded back from the front side to the back side of the panel body in parallel with the parallel direction of the receiving electrode, and at least a part of the drawer part formed in a substantially radial shape is an area in which the drawer part is close to the back plate. To be configured to be connected to the transmitter .

According to this, the longer the length of the lead wire and the larger the induced noise in the receiving electrode, the longer the part along the conductive back plate, and the induced noise can be reduced. It can be made small and uniform, thereby reducing variations in sensitivity of touch position detection .

  In this case, the back plate is preferably grounded. Thereby, the effect of induction noise reduction is enhanced. In addition, the grounding of the transmitter fixed to the back plate can be performed by the back plate.

A second invention made to solve the above-mentioned problems is that, in the first invention , the panel body has a support body disposed between the transmission electrode, the reception electrode and the back plate. The back plate has a side plate portion that is provided in a form bent from the main body portion along the back surface of the support body to the side surface side of the support body.

  According to this, since the rigidity of the back plate is increased, it is possible to increase the rigidity of the entire panel body and prevent the panel body from being deformed. In addition, since the portion of the lead wire along the conductive back plate becomes long, the induction noise of the receiving electrode can be further reduced.

According to a third aspect of the present invention for solving the above-described problems, in the first or second aspect of the invention, the panel main body is formed on a support sheet formed of a synthetic resin material having flexibility. It has an electrode sheet in which receiving electrodes are arranged, and this electrode sheet has a structure in which a lead portion in a form in which the lead wire is arranged in an extending portion of the support sheet is integrally provided.

  According to this, the lead line can be formed in the same process as the electrode, and since the lead line can be folded back to the back side simply by bending the lead part of the electrode sheet, the manufacturing becomes easy and the manufacturing is easy. Cost can be reduced.

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

  FIG. 1 is an overall configuration diagram showing a touch panel device according to the present invention. The touch panel device 1 includes a panel body 4 in which a plurality of transmission electrodes 2 that run parallel to each other and a plurality of reception electrodes 3 that run parallel to each other are arranged in a grid pattern, and drive signals (pulse signals) to the transmission electrodes 2. Level signal for each electrode intersection where the transmission electrode 2 and the reception electrode 3 intersect each other by receiving the charge / discharge current signal of the reception electrode 3 in response to the drive signal applied to the transmission electrode 2 And a control unit 7 that detects the touch position based on the level signal output from the reception unit 6 and controls the operations of the transmission unit 5 and the reception unit 6.

  The touch panel device 1 is used as a so-called interactive whiteboard that can be used for presentations and lectures by being combined with a large-screen display device. In particular, the touch panel device 1 is used in combination with a projector device. The touch surface of 1 serves as a projector screen.

  Touch position information output from the touch panel device 1 is input to an external device 8 such as a personal computer, and is projected and displayed on the touch surface of the touch panel device 1 by the projector device 9 based on display screen data output from the external device 8. On the display screen, an image corresponding to the touch operation performed by the user with the pointing object (conductor such as the user's fingertip and stylus or pointer) on the touch surface of the touch panel device 1 is displayed, and the touch surface of the touch panel device is displayed. It is possible to display a required image in the same manner as when directly drawing with a marker, and it is possible to operate buttons and the like displayed on the display screen. Furthermore, an eraser that erases an image drawn by a touch operation can be used.

  The transmission electrode 2 and the reception electrode 3 are arranged at the same arrangement pitch (for example, 10 mm), and the number thereof varies depending on the aspect ratio of the panel body 4. For example, the transmission electrode 2 is 120 and the reception electrode 3 is 186, for example. Book placed.

  The transmission electrode 2 and the reception electrode 3 intersect with each other in an overlapping manner with an insulating layer (a support sheet described later) interposed therebetween, and a capacitor is formed at an electrode intersection where the transmission electrode 2 and the reception electrode 3 intersect, When the user performs a touch operation with the indicator, the presence or absence of the touch operation can be detected by substantially reducing the capacitance at the electrode intersection in accordance with the touch operation.

  In particular, here, the mutual capacitance method is adopted, and when a drive signal is applied to the transmission electrode 2, a charge / discharge current flows to the reception electrode 3 in response to this, and at this time, according to the touch operation of the user, When the capacitance changes, the charging / discharging current of the receiving electrode 3 changes, and the amount of change of the charging / discharging current is converted into a level signal (digital signal) for each electrode intersection by the receiving unit 6 and output to the control unit 7. In the control unit 7, the touch position is calculated based on the level signal for each electrode intersection. This mutual capacitance method enables so-called multi-touch (multi-point detection) in which a plurality of touch positions are detected simultaneously.

  The control unit 7 obtains the touch position (center coordinate of the touch area) from the level signal for each electrode intersection output from the receiving unit 6 by a predetermined calculation process. In the calculation of the touch position, from the level signals at a plurality of (for example, 4 × 4) electrode intersections adjacent in the X direction (extension direction of the transmission electrode 2) and the Y direction (extension direction of the reception electrode 3), respectively. The touch position is obtained using a required interpolation method (for example, the center of gravity method). Thereby, the touch position can be detected with a resolution (for example, 1 mm or less) higher than the arrangement pitch (10 mm) of the transmission electrode 2 and the reception electrode 3.

  FIG. 2 is a schematic configuration diagram of the transmission unit 5 shown in FIG. The transmission unit 5 includes a drive signal generation unit 11 and an electrode selection unit 12. The drive signal generator 11 generates a drive signal (pulse signal) in synchronization with the timing signal output from the controller 7. In the electrode selection unit 12, a switching element is connected to each transmission electrode 2, the transmission electrode 2 is selected one by one, and the drive signal output from the drive signal generation unit 11 is sequentially applied to the transmission electrode 2.

  FIG. 3 is a schematic configuration diagram of the receiving unit 6 shown in FIG. The reception unit 6 includes an electrode selection unit 21 and a reception signal processing unit 22. In the electrode selection unit 21, a switching element is connected to each reception electrode 3, and the reception electrode 3 is selected one by one while applying a drive signal to one transmission electrode 2. The charge / discharge current signal is sequentially input to the reception signal processing unit 22. Thereby, the charge / discharge current signal for every electrode intersection can be taken out.

  The receiving electrodes 3 and the switching elements SW of the electrode selection unit 21 are grouped by a predetermined number (for example, 24), and corresponding switching elements SW belonging to each group are turned on / off in parallel. . A reception signal processing unit 22 is provided for each group. In each group, the switching elements SW are controlled so as to be sequentially turned on one by one, the remaining switching elements SW are controlled to be turned off, and one receiving electrode 3 selected by turning on the switching elements SW. The charge / discharge current signal is input to the reception signal processing unit 22.

  As described above, since the switching operation of the switching element SW is performed in parallel among a plurality of groups, the time required to receive the charge / discharge current signals of all the reception electrodes 3 can be shortened. Moreover, since the process of the charging / discharging current signal in the receiving unit 6 can be divided and performed for each group, an increase in the size of the hardware configuration can be suppressed.

  In the grouping of the reception electrodes 3, the number of reception electrodes 3 belonging to each group does not need to be the same. For example, when the number of reception electrodes 3 is 186, seven groups A to G are set to 24, and the last What is necessary is just to make 18 groups H.

  FIG. 4 is a schematic configuration diagram of the received signal processing unit 22 shown in FIG. The reception signal processing unit 22 includes an IV conversion unit 31, a band pass filter 32, an absolute value detection unit 33, an integration unit 34, a sample hold unit 35, and an AD conversion unit 36.

  In the IV conversion unit 31, the charge / discharge current signal (analog signal) of the reception electrode 3 input via the switching element SW is converted into a voltage signal. In the band pass filter 32, a process for removing a signal having a frequency component other than the frequency of the drive signal applied to the transmission electrode 2 is performed on the output signal of the IV conversion unit 31. The absolute value detection unit (rectification unit) 33 performs full-wave rectification on the output signal of the bandpass filter 32. The integration unit 34 performs processing for integrating the output signal of the absolute value detection unit 33 in the time axis direction. In the sample hold unit 35, a process of sampling the output signal of the integration unit 34 at a predetermined timing is performed. The AD converter 36 AD-converts the output signal from the sample hold unit 35 and outputs a level signal (digital signal).

  FIG. 5 is a plan view showing an electrode sheet 42 constituting the panel body 4 shown in FIG. The transmission electrode 2 and the reception electrode 3 are respectively disposed on the front and back surfaces of a support sheet 41 formed of a flexible synthetic resin material. The support sheet 41, the transmission electrode 2 and the reception electrode 3 are connected to each other. The electrode sheet 42 is constituted by being integrated.

  The transmission electrode 2 and the reception electrode 3 are formed with a width of 0.6 mm, for example. The transmission electrode 2 and the reception electrode 3 are formed by attaching an electrode forming material to the support sheet 41 in a predetermined pattern and performing a baking process that promotes hardening of the electrode forming material. In order to attach the electrode forming material to the support sheet 41, for example, a screen printing method may be used. In addition, an ink jet method or a nozzle printing method may be used.

  The electrode forming material for forming the transmission electrode 2 and the reception electrode 3 is a so-called conductive ink, and is suitable for conductive fillers that impart conductivity such as metal powder, binder resin for uniformly dispersing them, and screen printing. It consists of an organic solvent for obtaining fluidity and a pigment for confirming the adhesion state. As this electrode forming material, an Ag paste using Ag as a conductive filler is suitable.

  The support sheet 41 functions as an insulating layer that is interposed between the transmitting electrode 2 and the receiving electrode 3 and insulates them, and is formed of a synthetic resin material that is flexible and highly insulating. As the synthetic resin material of the support sheet 41, PET (Polyethylene terephthalate) is suitable. Moreover, the thickness of the support sheet 41 can manage the electrostatic capacitance of the capacitor formed at the electrode intersection, and the thickness of the support sheet 41 is preferably about 0.1 to 0.2 mm, for example.

  The electrode sheet 42 is integrally provided with a transmission-side lead portion 43 in a form in which a lead line connecting each of the transmission electrodes 2 and the transmission portion 5 is provided at a portion extending from the left side edge portion of the support sheet 41. Is provided. In addition, the electrode sheet 42 is integrally provided with a receiving side lead portion 44 in a form in which a lead line connecting each of the receiving electrodes 3 and the receiving portion 6 is provided in a portion extending from the lower edge portion of the support sheet 41. Provided. Here, one transmission-side extraction unit 43 and two reception-side extraction units 44 are provided.

  Although the wiring situation of the lead lines of the transmission side lead part 43 and the reception side lead part 44 will be described in detail later, this lead line is formed on the support sheet 41 in the same process as the transmission electrode 2 and the reception electrode 3 described above. The transmission electrode 2 and the reception electrode 3 are formed by the same conductive ink (electrode forming material) as the transmission electrode 2 and the reception electrode 3 in a mode in which the transmission electrode 2 and the reception electrode 3 are stretched by screen printing or the like.

  6 is a cross-sectional view of the panel body 4 shown in FIG. The panel body 4 includes a touch surface 51, and includes a surface plate 52 disposed on the front side of the electrode sheet 42, a back plate 53 disposed on the back side of the electrode sheet 42, and the electrode sheet 42 and the back plate 53. And a support 54 disposed therebetween. The surface plate 52 is formed of a synthetic resin material having a high dielectric constant, for example, a melamine resin, in order to increase the detection sensitivity of the touch operation by the indicator. The support 54 supports the electrode sheet 42 with appropriate elasticity, and is interposed between the electrode sheet 42 and the back plate 53 to insulate them, and has a synthetic resin material having elasticity, such as a foamed urethane resin. Is formed.

  FIG. 7 is a rear view of the panel body 4 shown in FIG. The back plate 53 is provided with one transmission board 61 constituting the transmission unit 5 and two reception boards 62 constituting the reception unit 6. The back plate 53 is formed of a conductive material and is grounded, and the transmission substrate 61 and the reception substrate 62 are grounded by the back plate 53. The transmission-side drawing portion 43 and the reception-side drawing portion 44 of the electrode sheet 42 are folded back to the back side of the panel body 4 and connected to the connectors 63 and 64 of the transmission board 61 and the reception board 62.

  In particular, here, the back plate 53 is formed of a metal material such as a steel plate. Thereby, the rigidity of the whole panel main body 4 can be improved, and a deformation | transformation of a panel main body can be prevented. In addition, by forming the back plate 53 with a conductive material, the induction noise of the receiving electrode 3 can be reduced as will be described in detail later.

  FIG. 8 is a plan view showing in detail the transmission side lead-out portion 43 of the electrode sheet 42 shown in FIG. In the transmission side lead-out portion 43, lead lines 71 that connect each of the transmission electrodes 2 and the transmission substrate 61 are disposed. The lead lines 71 are gathered substantially radially from one end side drawn from the transmission electrode 2 toward the other end side connected to the transmission board 61 so as to conform to the width of the connector 63 of the transmission board 61. It is arranged.

  In the portion 72 on the transmission electrode 2 side in the transmission side lead portion 43, the lead wire 71 extends in a direction greatly inclined with respect to the extending direction of the transmission electrode 2, and the lead wire 71 is substantially parallel to the reception electrode 3. In this way, the lead wire 71 is substantially parallel to the reception electrode 3, so that induction noise is generated in the reception electrode 3 due to the magnetic field generated by the drive signal flowing through the lead wire 71.

  In a portion 73 on the transmission board 61 side in the transmission side extraction portion 43, the extraction line 71 extends in the extending direction of the transmission electrode 2. Here, the lead wire 71 is divided and connected to a plurality of (here, three) connectors 63 provided on the transmission board 61. That is, the connection part 74 of the aspect which branched the transmission side drawer | drawing-out part 43 into plurality is provided, and this connection part 74 is inserted in each connector 63 of the transmission board | substrate 61. FIG.

  By arranging the lead lines 71 so as to be gathered substantially radially in this way, each lead line 71 connects the transmission electrode 2 and the transmission board 61 along a route close to the shortest distance. Can be shortened.

  The total length of each lead line 71 differs depending on the positional relationship between the transmission board 61 and the transmission electrode 2, and the total length of the lead line 71 increases as the distance between the transmission board 61 and the transmission electrode 2 increases. Here, the longest is the one corresponding to the transmission electrode 2 located at the end in the Y direction (the arrangement direction of the transmission electrodes 2), the length is gradually shortened toward the central portion in the Y direction, and the shortest in the central portion in the Y direction. Become.

  FIG. 8 shows an upper part from the center part of the transmission-side drawer 43, but the lower part appears substantially symmetrically with this.

  FIG. 9 is a plan view showing in detail the receiving side lead-out portion 44 of the electrode sheet 42 shown in FIG. In the reception side lead-out portion 44, lead lines 75 that connect each of the reception electrodes 3 and the reception substrate 62 are disposed. The lead wires 75 are gathered substantially radially from one end side pulled out from the receiving electrode 3 toward the other end side connected to the receiving substrate 62 so as to match the width of the connector 64 of the receiving substrate 62. It is arranged.

  In the portion 76 on the reception electrode 3 side in the reception side extraction portion 44, the extraction line 75 extends in a direction greatly inclined with respect to the extending direction of the reception electrode 3, and the extraction line 75 is substantially parallel to the transmission electrode 2. In this way, the lead wire 75 is substantially parallel to the transmission electrode 2, so that induced noise is generated in the lead wire 75 due to the magnetic field generated by the drive signal flowing through the transmission electrode 2.

In a portion 77 on the reception substrate 62 side in the reception side extraction portion 44 , the extraction line 75 extends in the extending direction of the reception electrode 3. Here, the lead wire 75 is divided and connected to a plurality of (here, three) connectors 64 provided on the receiving board 62. That is, the connection part 78 of the aspect which branched the receiving side drawer | drawing-out part 44 into plurality is provided, and this connection part 78 is inserted in each connector 64 of the receiving board 62. FIG.

  FIG. 9 shows one receiving side drawer 44, but the other receiving side drawer 44 appears approximately symmetrically.

  By the way, as shown in FIG. 6, the lead-out line 71 of the electrode sheet 42 is folded back to the back plate 53 side so that the lead line 71 is close to the back plate 53. As the back plate 53 approaches, the electrostatic capacity associated with the lead wire 71 increases, and the inductive action caused by the current due to the drive signal applied to the transmission electrode 2 flowing through the lead wire 71 can be suppressed. Therefore, by configuring the lead wire 71 along the conductive back plate 53 to be long, the effect of reducing the induction noise can be increased and the induction noise generated in the receiving electrode 3 can be reduced. .

  On the other hand, as shown in FIG. 8, the lead lines 71 are arranged so as to be gathered substantially radially, so that the total length of the lead lines 71 is different, and the longer the total length of the lead lines 71 is, the larger the induction noise becomes. Is generated. For this reason, when the length along the conductive back plate 53 becomes longer as the length of the lead wire 71 becomes longer, the effect of reducing the induced noise can be increased according to the magnitude of the induced noise. .

  FIG. 10A is a schematic plan view showing a wiring pattern of the transmission side lead-out portion 43 of the electrode sheet 42 shown in FIG. As described above, by folding back the transmission-side lead portion 43 of the electrode sheet 42 toward the back plate 53 side, at least a part of the portion where the lead wires 71 gather substantially radially is disposed along the back plate 53. As the length of the leader line 71 is longer and generates a larger induced noise, the portion along the conductive back plate 53 becomes longer, and the effect of reducing the induced noise becomes greater. For this reason, the induction noise of the receiving electrode 3 can be made small and uniform.

  FIG. 10B is a schematic plan view showing a modification of the wiring pattern of the transmission side lead-out portion 43 of the electrode sheet 42 shown in FIG. Here, the lead wire 71 is disposed in a manner bent at a right angle. In this configuration, the entire length of the lead wire 71 becomes longer according to the separation distance between the connection portion 74 and the transmission electrode 2, but by folding the transmission side lead portion 43 toward the back plate 53, The length of the portion along the line is the same for all the leader lines 71 regardless of the length of the leader line 71. For this reason, as shown in FIG. 10A, the advantage that the effect of reducing the induction noise increases according to the length of the lead line 71 cannot be obtained.

  FIG. 11 is a diagram showing the difference in the degree of variation in reception sensitivity due to the difference in the separation distance D between the transmission-side drawer 43 and the back plate 53 shown in FIG. FIG. 11A shows a case where the transmission-side lead portion 43, that is, the transmission-side lead wire 71 is brought close to the back plate 53 (first example), and FIG. 11B shows the lead wire 71 and the back plate 53. In the case where they are separated (second example), there is a difference of 10 mm in the separation distance D between the transmission-side drawer 43 and the back plate 53 (see FIG. 6).

  Here, the horizontal axis indicates the position in the Y direction (the arrangement direction of the transmission electrodes 2). The vertical axis represents the received voltage obtained by IV conversion of the charge / discharge current signal flowing in the receiving electrode 3 in response to the application of the drive signal (pulse signal) to the transmitting electrode 2, and here, the 30th from the end, The reception voltages of the 60th, 90th, and 120th reception electrodes (X = 30, 60, 90, 120) are shown.

  FIG. 12 is a plan view showing the effect of improving the variation in reception sensitivity by bringing the transmission line 71 on the transmission side close to the back plate 53. This is because the first example shown in FIG. 11A, that is, the reception voltage when the leader line 71 is brought close to the back plate 53, and the second example shown in FIG. A difference δ from the reception voltage when spaced apart from 53 is shown in a plane in the X direction (the arrangement direction of the reception electrodes 3) and the Y direction (the arrangement direction of the transmission electrodes 2).

  As shown in FIG. 11A, when the lead line 71 is close to the back plate 53, the reception voltage is low overall, and as shown in FIG. When it is away from 53, the received voltage becomes high as a whole. This indicates that the induction noise is reduced as a whole by bringing the lead line 71 close to the back plate 53.

  Further, the reception voltage is high at the end in the Y direction (the direction in which the transmission electrodes 2 are arranged) and low at the center in the Y direction. This indicates that the reception voltage, which should be substantially uniform, varies due to the influence of the induction noise, and the induction noise is large at the end portion in the Y direction and small at the center portion in the Y direction. The difference in the magnitude of the induced noise is caused by the length of the leader line 71 depending on the position in the Y direction, and the induced noise becomes larger at the end in the Y direction where the leader line 71 becomes longer. Inductive noise is reduced at the center in the Y direction where the lead line 71 becomes shorter.

  Δ1 shown in the figure is the difference between the reception voltage of the first example and the second example regarding the reception voltage showing the highest value at the end in the Y direction, and δ2 is the reception voltage showing the lowest value in the center of the Y direction. Δ1 is larger than δ2 (δ1> δ2). This indicates that the induced noise is greatly reduced at the end portion in the Y direction where the induced noise is large, and the induced noise is reduced small at the center portion in the Y direction where the induced noise is small (see FIG. 12).

  When the lead wire 71 is brought close to the back plate 53 in this manner, the induction noise can be reduced, and the effect that the induction noise is reduced increases as the large induction noise is generated with respect to the position in the Y direction. Inductive noise can be made small and uniform, thereby reducing variations in sensitivity of touch position detection.

  Note that the conductive back plate 53 has a shielding effect for shielding the magnetic field, and the induction noise generated in the receiving electrode 3 is reduced by this shielding effect. Specifically, in the transmission side lead-out part 43, the conductive back plate 53 blocks a magnetic field generated around the lead line 71 and reduces induction noise generated in the reception electrode 3. Further, in the reception side lead-out portion 44, the conductive back plate 53 blocks a magnetic field generated around the transmission electrode 2 and reduces induction noise generated in the reception side lead wire 75.

  FIG. 13 is a schematic sectional view showing a modification of the panel body 4 shown in FIG. Here, similarly to the example shown in FIG. 6, the back plate 91 is formed of a conductive material (for example, a metal material such as a steel plate). In particular, here, the back plate 91 is formed of the support 54. It has a side plate portion 93 provided in a manner bent from the main body portion 92 along the back surface to the side surface side of the support body 54. The side plate portions 93 are provided on the four sides on the top, bottom, left, and right of the back plate 91, and the back plate 91 has a bottomed box shape as a whole.

  If comprised in this way, since the rigidity of the backplate 91 will become high, the rigidity of the whole panel main body 4 can be improved, and a deformation | transformation of the panel main body 4 can be prevented. In addition, the lead wire 71 is in a state along the side plate portion 93 in addition to the main body portion 92, and the portion of the lead wire 71 along the outer surface of the back plate 91 becomes longer, so that the induction noise of the receiving electrode 3 is further reduced. can do.

  In particular, as shown in FIG. 10, when the portion where the leader lines 71 gather substantially radially enters the region facing the side surface of the support 54, the side plate portion 93 of the back plate 91 is located here. Therefore, the region where the portions where the leader lines 71 are gathered substantially radially extends along the conductive back plate 91 is enlarged. For this reason, the effect of the induction noise reduction according to the full length of the leader line 71 improves further.

  FIG. 14 is a schematic cross-sectional view showing a modified example of the panel body 4 shown in FIG. Here, a cover member 101 that covers the transmission side lead-out portion 43 of the electrode sheet 42 is provided on the side edge of the panel body 4. The cover member 101 is formed of a conductive material and is grounded. Note that the cover member 101 may be formed of a synthetic resin material having conductivity, but a configuration in which conductivity is imparted by application of a conductive paint or the like is also possible.

  In this configuration, since the conductive cover member 101 is close to the lead wire 71, the receiving electrode 3 is not easily affected by the inductive action caused by the current due to the drive signal flowing through the lead wire 71, and the induction noise of the receiving electrode 3 is reduced. Can be further reduced.

  The touch panel device according to the present invention has an effect of reducing the induction noise generated in the receiving electrode due to the inductive action caused by the current due to the drive signal applied to the transmitting electrode flowing in the lead wire, and the capacitance It is useful as a touch panel device that detects a touch position by a method, particularly a mutual capacitance method.

DESCRIPTION OF SYMBOLS 1 Touch panel apparatus 2 Transmission electrode 3 Reception electrode 4 Panel main body 5 Transmission part 6 Reception part 7 Control part 41 Support sheet 42 Electrode sheet 43 Transmission side extraction part 44 Reception side extraction part 51 Touch surface 52 Surface board 53 Back board 54 Support body 61 Transmission board 62 Reception board 71 Transmission-side lead wire 75 Reception-side lead wire 91 Back plate 92 Body portion 93 Side plate portion

Claims (3)

A panel body in which a plurality of transmitting electrodes that run in parallel with each other and a plurality of receiving electrodes that run in parallel with each other are arranged in a lattice pattern;
A transmission unit that applies a drive signal to the transmission electrode;
A receiving unit that receives a charge / discharge current signal of the receiving electrode in response to a drive signal applied to the transmitting electrode and outputs a level signal for each electrode intersection;
A lead portion formed between the transmission portion and the transmission electrode in a substantially radial manner and having a lead wire disposed so as to gather from one end side toward the other end side ;
The panel body is formed of a conductive plate and a rear surface of the transmission electrode and the reception electrode, and a surface plate disposed on the front surface of the transmission electrode and the reception electrode. The transmitter is fixed to the back plate, and the lead-out portion is folded back from the front side of the panel body to the back side in parallel with the parallel direction of the reception electrode. A touch panel device , wherein at least a part of the drawer part formed radially is connected to the transmission part in a region close to the back plate . The panel body has a support body disposed between the transmission electrode and the reception electrode and the back plate,
2. The touch panel device according to claim 1, wherein the back plate includes a side plate portion that is provided in a form bent from a main body portion along a back surface of the support body to a side surface side of the support body. The panel body has an electrode sheet in which the transmitting electrode and the receiving electrode are arranged on a support sheet formed of a synthetic resin material having flexibility, and an extension portion of the support sheet is provided on the electrode sheet. the drawer unit in the touch panel device according to claim 1 or claim 2, characterized in that integrally provided.

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