JP2014081892A - Touch panel system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a touch panel system such that detection precision of an indication body is high.SOLUTION: A touch panel system 1 includes a touch panel 10 including a plurality of drive lines DL and a plurality of sense lines SL; a drive line driving part 20 which drives the plurality of drive lines DL; and a sense signal processing part 30 which generates a capacity signal Ei indicating an in-plane distribution of capacitance that a drive line DL and a sense line SL form. The sense signal processing part 30 compares processing results of sense signals Si obtained in a plurality of predetermined successive driving periods before an object driving period, and averages processing results of sense signals Si obtained in the plurality of predetermined driving periods before the object driving period so as to generate a capacitance signal Ei in the object driving period when the plurality of compared processing results separate exceeding a predetermined standard.

Description

  The present invention relates to a touch panel system including a projected capacitive touch panel, and an electronic information device including the touch panel system.

  2. Description of the Related Art In recent years, touch panel systems that accept user instructions by detecting the position of an indicator (for example, a user's finger or a touch pen, the same applies hereinafter) that is in contact with or close to the detection surface of the touch panel have become electronic devices such as mobile phones and personal computers. Increasingly mounted on information equipment. In particular, projection capacitive touch panels capable of multi-touch are increasingly mounted on electronic information devices.

  As a projected capacitive touch panel system, a plurality of drive lines provided parallel to each other along the detection surface of the touch panel and a plurality of sense lines provided parallel to each other along the detection surface and intersecting the drive lines There is a thing provided with. In this touch panel system, a predetermined signal (hereinafter referred to as “drive signal”) is applied to the drive line to drive, thereby acquiring and processing a signal appearing on the sense line (hereinafter referred to as “sense signal”). The position of the indicator that is in contact with or close to the detection surface is detected.

  The sense signal appearing on the sense line corresponds to a capacitance (hereinafter simply referred to as “capacitance”) formed by the sense line and a drive line that intersects the sense line and is driven. In this touch panel system, the sense signal appearing on each sense line is processed to determine the in-plane distribution of the capacity, and the position where the capacity is different from the normal capacity without the indicator is displayed on the detection surface. It detects as the position of the indicator which touches or adjoins.

  For example, as the above touch panel system, there is one that obtains an in-plane distribution of capacity by sequentially driving one drive line at a time. A touch panel that obtains an in-plane distribution of capacitance by driving a plurality of drive lines with orthogonal drive signals and performing a predetermined operation such as inner product on the sense signals obtained accordingly. A system is proposed in US Pat.

  In the touch panel system proposed in Patent Document 1, the capacitance at the same position in the detection surface is added in a superimposed manner in the process of performing a predetermined calculation on the sense signal. Therefore, it is possible to increase the SN (Signal to Noise) ratio as compared with a touch panel system that sequentially drives one drive line at a time.

JP 2012-118957 A

  However, in the touch panel system proposed in Patent Document 1, when the in-plane distribution of capacitance is obtained, drive lines are driven as many as the number of drive lines, and sense signals are acquired as many as the number of drive lines. There is a need. That is, in this touch panel system, an indicator on the touch panel is detected not during a certain moment but during a period in which the drive line is driven a predetermined number of times (hereinafter referred to as “driving period”). For this reason, if the capacitance fluctuates steeply during this driving period, the calculation accuracy of the capacitance is lowered, and the detection accuracy of the indicator is lowered. In particular, in this touch panel system, if the capacitance at some positions in the detection surface changes steeply during the drive period, not only will the result of calculating the capacitance at that position change, but also the capacitance at a position unrelated to that position. Since the calculation result may vary, it becomes a problem.

  Note that the above-mentioned problem is noticeable in conventional touch panel systems such as a touch panel system in which the detection surface of the touch panel is not so large (the number of drive lines is not so many) and a touch panel system applied to an electronic information device that is slow to be operated by the user. It can be ignored. However, in recent years, touch panel systems have become increasingly large, and application of touch panel systems to electronic information devices (for example, video game machines) that are fast to operate by users has progressed. In the future, the above problems may be ignored. Expected to be impossible.

  Therefore, the present invention provides a touch panel system with high indicator detection accuracy and an electronic information device including the touch panel system.

  To achieve the above object, the present invention provides a plurality of drive lines provided parallel to each other along the detection surface, and a plurality of sense lines provided parallel to each other along the detection surface and intersecting the drive lines. , A drive line drive unit that is driven by sequentially applying drive signals to the plurality of drive lines, and the sense line during the drive period that is a period for driving the drive lines a predetermined number of times. The touch panel based on the capacitance signal, and a sense signal processing unit that generates a capacitance signal indicating an in-plane distribution of capacitance formed by the drive line and the sense line by sequentially acquiring and processing the sense signal that appears. An indicator position detecting unit that detects the position of the indicator that is in contact with or close to the detection surface of When generating the capacitance signal in the target driving period, the sense signal processing unit outputs a predetermined plurality of consecutive processing results of the sense signal obtained in the driving period before the target driving period. When the plurality of processing results compared with each other are deviated beyond a predetermined reference, the drive of the target is generated when generating the capacity signal in the drive period of the target. A touch panel system is provided, wherein the processing result of the sense signal obtained in the driving period before the period is averaged for a plurality of consecutive predetermined driving periods.

  Further, in the touch panel system having the above characteristics, when X is a natural number of 2 or more and K is a natural number larger than X, the sense signal processing unit generates the capacitance signal in the Kth driving period. The processing result of the sense signal obtained in the K-Xth driving period is compared with the processing result of the sense signal obtained in the K-X + 1-th driving period. When the processing result deviates beyond a predetermined reference, the K-X + 1th to Kth driving periods obtained when generating the capacitance signal in the Kth driving period are obtained. It is preferable to average the processing results of the sense signal.

  Further, in the touch panel system having the above characteristics, when X is a natural number of 2 or more and K is a natural number larger than X, the sense signal processing unit generates the capacitance signal in the Kth driving period. The processing result of the sense signal obtained in the K-Xth driving period is compared with the processing result of the sense signal obtained in the K-X + 1-th driving period. When the processing result does not deviate beyond a predetermined reference, when generating the capacitance signal in the Kth driving period, the sense signal obtained in the (K−X + 1) th driving period is generated. It is preferable to use the processing result.

  Furthermore, in the touch panel system having the above characteristics, it is preferable that X is 3 or less.

  Furthermore, in the touch panel system having the above characteristics, the processing result includes the drive line and the sense line that are generated by the sense signal processing unit processing the sense signal obtained in one driving period. It may be a provisional capacity signal indicating the in-plane distribution of capacity.

  Furthermore, in the touch panel system having the above characteristics, it is preferable that the sense signal processing unit compares a capacitance at the same position in the detection surface indicated by the provisional capacitance signal.

  Furthermore, in the touch panel system having the above characteristics, the processing result indicates a signal value of each sense signal generated by the sense signal processing unit processing each sense signal appearing on each sense line. It may be a signal after provisional processing.

  Furthermore, in the touch panel system having the above characteristics, it is preferable that the sense signal processing unit compares signal values of the sense signals obtained from the same sense line indicated by the provisional post-processing signal.

  Furthermore, in the touch panel system having the above characteristics, it is preferable that the component of the drive signal given to the plurality of drive lines is an orthogonal sequence or an M sequence.

  The present invention also provides an electronic information device characterized by including the touch panel system having the above characteristics.

  According to the touch panel system and the electronic information device having the above characteristics, the capacitance at a position unrelated to the position in the capacitance signal is apparent because the capacitance at a part of the detection surface changes steeply during the driving period. In the case where the fluctuation may occur (on the calculation result), the sense signal processing unit suppresses the apparent fluctuation (on the calculation result) by averaging the processing result of the sense signal when generating the capacitance signal. To do. Therefore, the detection accuracy of the indicator in the touch panel system can be increased.

The block diagram which shows an example of the whole structure of the touchscreen system which concerns on embodiment of this invention. The top view and circuit diagram which are shown about an example of the structure of the drive line and sense line with which the touch panel of FIG. 1 is provided. The figure explaining the orthogonal parallel drive of a touch panel. The figure explaining the decoding method of the signal after a process in the case of performing the orthogonal parallel drive of FIG. 3 with respect to a touch panel. The flowchart shown about an example of the correction method (capacitance signal generation method) of the provisional capacity | capacitance signal by a correction | amendment part. The table | surface shown about the specific example of the correction method (capacitance signal generation method) of the provisional capacity | capacitance signal by a correction | amendment part. The block diagram which shows the structural example of the electronic information apparatus which concerns on embodiment of this invention. The block diagram which shows an example of the whole structure of the touchscreen system which concerns on another embodiment of this invention.

<< Touch panel system >>
<Whole touch panel system>
Hereinafter, a touch panel system according to an embodiment of the present invention will be described with reference to the drawings. First, an example of the overall structure and operation of a touch panel system according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

  FIG. 1 is a block diagram showing an example of the overall structure of a touch panel system according to an embodiment of the present invention. 2 is a plan view and a circuit diagram showing an example of the structure of drive lines and sense lines provided in the touch panel of FIG. 2A is a plan view showing the structure of the drive line DL and the sense line SL provided in the touch panel 10, and FIG. 2B is a circuit diagram showing an equivalent circuit of FIG. 2A. .

  As shown in FIG. 1, the touch panel system 1 includes a plurality of drive lines DL provided in parallel with each other along the detection surface P and a plurality of senses provided in parallel with each other along the detection surface P and intersecting with the drive lines DL. Touch panel 10 including line SL, drive line drive unit 20 that is driven by sequentially applying drive signals Di to a plurality of drive lines DL, and a drive period that is a period for driving drive lines DL a predetermined number of times A sense signal processing unit 30 for generating a capacitance signal Ei indicating an in-plane distribution of capacitance formed by the drive line DL and the sense line SL by sequentially acquiring and processing the sense signal Si appearing on the sense line SL; Based on Ei, the detection result signal Ti is detected by detecting the position of the indicator in contact with or close to the detection surface P. A pointer position detection unit 40 to be generated, a clock signal generation unit 50 that generates a clock signal CLK, a touch panel control unit 60 that operates the drive line driving unit 20 and the sense signal processing unit 30 at a timing synchronized with the clock signal CLK, and .

  The drive line DL included in the touch panel 10 is provided so as to extend along the X direction (vertical direction in the drawing). On the other hand, the sense line SL provided in the touch panel 10 is provided so as to extend along the Y direction (left-right direction in the drawing) perpendicular to the X direction. That is, in the touch panel system 1 shown in FIG. 1, the drive line DL and the sense line SL intersect perpendicularly. Note that the drive line DL and the sense line SL may intersect at an angle other than vertical.

  Further, as shown in FIGS. 2A and 2B, the drive line DL includes a drive line pad portion DLP having a locally increased area except for a portion intersecting with the sense line SL. Similarly, the sense line SL includes a sense line pad portion SLP having a locally increased area except for a portion intersecting the drive line DL. As shown in FIGS. 2A and 2B, a capacitor C is formed between the drive line DL and the sense line SL at a portion where the drive line DL and the sense line SL intersect.

  In the example shown in FIG. 2A, a capacitor C is mainly formed between the adjacent drive line pad portion DLP and sense line pad portion SLP. The drive line DL may not include the drive line pad portion DLP, and the sense line SL may not include the sense line pad portion SLP. Even in this case, a capacitor is formed at the intersection of the drive line DL and the sense line SL.

  The drive line drive unit 20 drives the drive line DL by applying a drive signal Di that fluctuates at a predetermined timing and in a predetermined pattern to the drive line DL according to control by the touch panel control unit 60.

  The sense signal processing unit 30 includes a sense signal acquisition unit 31, a decoding processing unit 32, a correction unit 33, and a storage unit 34.

  The sense signal acquisition unit 31 acquires the sense signal Si appearing on the sense line SL at a predetermined timing in accordance with control by the touch panel control unit 60, and generates a processed signal Ai by performing processing such as amplification and conversion. The decoding processing unit 32 generates the provisional capacity signal Ci by decoding the post-processing signal Ai according to the control by the touch panel control unit 60.

  The correcting unit 33 corrects the provisional capacity signal Ci obtained from the decoding processing unit 32 to generate the capacity signal Ei. The storage unit 34 sequentially stores the provisional capacity signal Ci sequentially generated by the decoding processing unit 32. The temporary capacity signal Ci stored in the storage unit 34 is used when the correction unit 33 corrects the temporary capacity signal Ci (details will be described later).

  Then, the indicator position detection unit 40 detects the position of the indicator that is in contact with or close to the detection surface P based on the capacitance signal Ei generated by the sense signal processing unit 30 (for example, the capacitance surface indicated by the capacitance signal Ei). The detection result signal Ti is generated by detecting the position where the capacity is reduced from the internal distribution.

  For example, the detection result signal Ti may include data indicating the number of detected indicators, the position of each indicator, and the degree of contact or proximity of each indicator to the detection surface P. And this detection result signal Ti is utilized as a signal which shows a user's instruction | indication in electronic information equipment provided with the touch panel system 1, for example.

<Touch panel drive method and provisional capacitance signal generation method>
Next, a specific operation example of each part of the touch panel system 1 described above will be described with reference to the drawings. First, a method of driving the touch panel 10 by the drive line driving unit 20 and a method of generating the provisional capacitance signal Ci by the sense signal acquiring unit 31 and the decoding processing unit 32 of the sense signal processing unit 30 will be described with reference to the drawings. . In the following, for the sake of concrete explanation, a case where the drive line driving unit 20 drives the touch panel 10 in an orthogonal parallel manner will be exemplified.

  The orthogonal parallel drive of the touch panel 10 will be described with reference to FIGS. 3 and 4. FIG. 3 is a diagram illustrating orthogonal parallel driving of the touch panel. FIG. 4 is a diagram for explaining a method of decoding a post-processing signal when the orthogonal parallel drive of FIG. 4 is performed on the touch panel. In FIG. 3, only one sense line SL1 and four drive lines DL1 to DL4 are shown for simplicity of explanation. The capacitances formed by the sense line SL1 and the drive lines D1 to D4 are C11 to C41.

  As shown in the upper block diagram of FIG. 3, the sense signal acquisition unit 31 has an inverting input terminal (−) to which the sense line SL1 is connected and an output terminal connected via an amplification capacitor Cint and a non-inverting input. An amplifier 311 composed of an operational amplifier whose terminal (+) is the ground voltage (GND), and a digital output value indicating the capacitances C11 to C41 while performing AD (Analog to Digital) conversion of the voltage value Vout of the output terminal of the amplifier 311 An output value generation unit 312 that outputs Cout (signal value). The post-process signal Ai is a signal indicating the output value Cout.

  Further, as shown in the lower table of FIG. 3, in the orthogonal parallel driving of the touch panel 10, “1” (positive voltage, + V) and “−1” (negative voltage) are applied to the drive lines DL1 to DL4. , -V) as a component. In the drive signal given to the drive lines DL1 to DL4, “1” and “−1” are sequentially changed, and are repeated at a predetermined cycle (a period in which the drive lines DL1 to DL4 are driven four times in this example). It is what

  In the orthogonal parallel driving, positive or negative charges are accumulated in each of the drive lines DL1 to DL4 by driving the drive lines DL1 to DL4. Therefore, a sense signal Si1 having a voltage value corresponding to a value obtained by adding or subtracting all the capacitors C11 to C41 appears on the sense line SL1, and the voltage value Vout of the output terminal of the amplifying unit 311 also includes the capacitors C11 to C11. It becomes a value corresponding to a value obtained by adding or subtracting C41.

  Specifically, in the first drive, since “1” is given to all of the drive lines DL1 to DL4, the voltage value Vout of the output terminal of the amplification unit 311 is Vout = (C11 + C21 + C31 + C41) · V / Cint. Become. At this time, since the voltage V and the amplification capacitance Cint are known, the output value generation unit 312 adds the capacitances C11 to C41 or simply performs a simple calculation on the voltage value Vout (multiply by Cint / V). An output value Cout combined by subtraction can be obtained. In the first driving, when the output value generation unit 312 performs an operation, an output value Cout indicating C11 + C21 + C31 + C41 is obtained.

  In the second drive, “1” is given to the drive lines DL1 and DL3 and “−1” is given to the drive lines DL2 and DL4. Vout is Vout = (C11−C21 + C31−C41) · V / Cint. The output value Cout indicating C11−C21 + C31−C41 is obtained by the calculation of the output value generation unit 312.

  In the third drive, “1” is given to the drive lines DL1 and DL2, and “−1” is given to the drive lines DL3 and DL4. Therefore, the voltage value of the output terminal of the amplifying unit 311 Vout is Vout = (C11 + C21−C31−C41) · V / Cint. Then, an output value Cout indicating C11 + C21−C31−C41 is obtained by the calculation of the output value generation unit 312.

  In the fourth drive, since “1” is given to the drive lines DL1 and DL4 and “−1” is given to the drive lines DL2 and DL3, the voltage value of the output terminal of the amplifier 311 Vout is Vout = (C11−C21−C31 + C41) · V / Cint. Then, the output value Cout indicating C11−C21−C31 + C41 is obtained by the calculation of the output value generation unit 312.

  In order to obtain the respective capacities C11 to C41 from the output value Cout obtained as described above, it is necessary to decode the output value Cout by the decoding processing unit 32 as shown in FIG. Note that FIG. 4 illustrates the case where the capacitors C11 to C44 formed by the four sense lines SL1 to SL4 and the drive lines DL1 to DL4 are obtained, but the drive signals given to the drive lines DL1 to DL4 are as follows. This is the same as FIG.

  Further, as shown in FIG. 4A, the capacitance formed by the sense line SL1 and the drive lines DL1 to DL4 is C11 to C41, and the capacitance formed by the sense line SL2 and the drive lines DL1 to DL4 is C12 to C42. The capacitance formed by SL3 and the drive lines DL1 to DL4 is C13 to C43, and the capacitance formed by the sense line SL4 and the drive lines DL1 to DL4 is C14 to C44. Further, the output value of the sense line SL1 during the first to fourth drive is Cout11 to Cout41, the output value of the sense line SL2 during the first to fourth drive is Cout12 to Cout42, and the first to fourth drive. The output values of the sense line SL3 are Cout13 to Cout43, and the output values of the sense line SL4 during the first to fourth driving are Cout14 to Cout44.

  In this case, as illustrated in FIG. 4B, the matrix “Cout” of the output values Cout11 to Cout44 is an inner product of the matrix “H” of the drive signal and the matrix “C” of the capacitors C11 to C44. The matrix “Cout” has sense lines SL1 to SL4 from which output values are obtained as rows and columns in which the output values are obtained as columns. The matrix “H” has drive lines DL1 to DL4 that supply drive signal components as rows, and the order in which the drive signal components are supplied as columns. Further, the matrix “C” has the capacitance along the direction (X direction) in which the drive lines DL1 to DL4 extend as rows and the capacitance along the direction (Y direction) in which the sense lines SL1 to SL4 extend as columns. .

  Here, for the sake of concrete explanation, attention is paid to the sense line SL1 and the capacitors C11 to C41 shown in FIG. The following description is also valid for the other sense lines SL2 to SL4 and the capacitors C12 to C42, C13 to C43, and C14 to C44.

  Cout11 that is a component of the first row and first column of the inner products “H” and “C” in FIG. 4B is expressed by the following equation (1). Similarly, Cout21 which is the component of the second row and first column of the inner product “H” / “C” is the following equation (2), and Cout31 which is the component of the third row and first column of the inner product “H” / “C”. Is the following equation (3), and Cout41 which is the component of the fourth row and first column of the inner product “H” / “C” is the following equation (4).

Cout11 = C11 + C21 + C31 + C41 (1)
Cout21 = C11−C21 + C31−C41 (2)
Cout31 = C11 + C21-C31-C41 (3)
Cout41 = C11−C21−C31 + C41 (4)

In the orthogonal parallel drive, the components “1” and “−1” of the drive signal given to the drive lines DL1 to DL4 are orthogonal sequences, so that the matrix “H” is an orthogonal matrix. Therefore, as shown in FIG. 4C, only the inner product of the transpose matrix (matrix in which the row components and the column components are exchanged) “H ^T ” and the matrix “Cout” of the drive signal matrix “H” is obtained. Thus, the matrix “C” (that is, the in-plane distribution of capacitance) can be obtained. In this example, the matrix “H ^T ” is equal to the matrix “H”.

Specifically, the calculation result of the first row and first column of the inner product “H ^T ” / “Cout” is expressed by the following equation (5). Similarly, the inner product "H ^T", the second row, first column of the operation result shown by the following formula "Cout" (6), and the inner product "H ^T ', third row operation result of the first column of the" Cout "is The following expression (7) is obtained, and the calculation result of the fourth row and first column of the inner product “H ^T ” / “Cout” is represented by the following expression (8). In addition, the right side of following formula (5)-(8) is calculated | required by substituting said formula (1)-(4) with respect to the left side of following formula (5)-(8), respectively.

Cout11 + Cout21 + Cout31 + Cout41 = 4 · C11 (5)
Cout11−Cout21 + Cout31−Cout41 = 4 · C21 (6)
Cout11 + Cout21−Cout31−Cout41 = 4 · C31 (7)
Cout11−Cout21−Cout31 + Cout41 = 4 · C41 (8)

As described above, in the orthogonal parallel drive, the capacity C11 to C41 (t in the example of FIG. 4) C11 to C41 is obtained by the decoding process (matrix operation) of the decoding processing unit 32, and thus the decoding processing unit 32 generates. In the provisional capacitance signal Ci, the influence of noise can be reduced to t ^1/2 times.

  However, the calculations of the above formulas (1) to (8) are based on the premise that the capacitors C11 to C41 do not vary during the driving period (during the first to fourth driving). Therefore, for example, when any one of the capacitors C11 to C41 changes steeply during the driving period due to, for example, an indicator contacting or approaching a part of the detection surface P, the changed capacitance is expressed by the above formula. The values are not unified in (1) to (4). Then, when solving the simultaneous equations as in the above formulas (5) to (8) to obtain the capacities C11 to C41, the capacities at positions unrelated to the capacities are correctly obtained under the influence of the fluctuating capacities. It may occur that the detection accuracy of the indicator is lowered.

  Therefore, as will be described below, in the touch panel system 1 according to the embodiment of the present invention, the capacitance at some positions in the detection surface P changes steeply during the driving period, so that the corresponding position in the capacitance signal Ei. When the capacity at a position unrelated to the position may fluctuate (on the calculation result), the correction unit 33 corrects the provisional capacity signal Ci when generating the capacity signal Ei, so that the apparent (calculation) Suppress fluctuations in the result.

<Temporary capacitance signal correction method>
A correction method of the provisional capacitance signal Ci (a generation method of the capacitance signal Ei) by the correction unit 33 will be described with reference to the drawings. FIG. 5 is a flowchart illustrating an example of a provisional capacitance signal correction method (capacitance signal generation method) by the correction unit. The flowchart shown in FIG. 5 shows the operation of the correction unit 33 when correcting one provisional capacitance signal Ci to generate one capacitance signal Ei, and is repeatedly performed.

  As shown in FIG. 5, first, the sense signal acquisition unit 31 and the decoding processing unit 32 perform the above-described processing (the above formulas (1) to (8)) on the sense signal Si obtained in the Kth driving period. The correction unit 33 acquires a provisional capacitance signal Ci (referred to as a provisional capacitance signal Ci for the K-th driving period) obtained by performing (see Step # 1). In addition, the storage unit 34 stores the provisional capacitance signal Ci for the Kth driving period.

  K is a time-series relationship (in particular, the order in which the drive periods are performed, the order in which the provisional capacitance signal Ci is generated, and the smaller the value, the earlier it has been generated). It is a variable introduced for convenience and is an integer of 3 or more. Note that either of these steps # 1 and # 2 may be performed first or at the same time.

  Next, the correction unit 33 reads the provisional capacitance signal Ci in the (K-2) th driving period and the provisional capacitance signal Ci in the (K-1) th driving period from the storage unit 34 (step # 3). And the correction | amendment part 33 compares the magnitude | size of the capacity | capacitance in the same position in the detection surface P about the provisional capacity | capacitance signal Ci of the K-2th and K-1th drive period read from the memory | storage part 34, The presence or absence of a change in capacity is detected (step # 4). Specifically, the correction unit 33 calculates the difference (absolute value) of the capacitance at each position in the detection plane P for the provisional capacitance signal Ci in the (K-2) th and (K-1) th driving periods, and the difference is calculated. It is checked whether or not there is a position that is equal to or greater than a predetermined threshold L (positive value) (step # 5).

  When there is no position where the difference in capacity at each position in the detection surface P is greater than or equal to the threshold L for the provisional capacity signal Ci in the (K-2) th and (K-1) th drive periods (step # 5, NO), the correction unit 33 outputs the provisional capacitance signal Ci in the (K-1) th driving period as the capacitance signal Ei in the Kth driving period (step # 6).

  Regarding the provisional capacitance signal Ci in the (K-2) th and (K-1) th driving periods, there is no position where the difference in capacitance at each position in the detection plane P is equal to or greater than the threshold value L. This is a case where there is no steep fluctuation of the capacitance on the entire detection surface P during the first drive period. That is, in this case, the apparent variation (in the calculation result) of the capacitance in the capacitance signal Ei as described above cannot occur. Therefore, in this case, the provisional capacitance signal Ci in the (K−1) th driving period is set as the capacitance signal Ei in the Kth driving period.

  On the other hand, if there is a position where the difference in capacity at each position in the detection surface P is equal to or greater than the threshold L for the provisional capacity signal Ci in the K-2th and K-1th drive periods (step # 5, YES). The correction unit 33 generates the capacitance signal Ei for the Kth driving period by averaging the provisional capacitance signal Ci for the (K−1) th driving period and the provisional capacitance signal Ci for the Kth driving period. (Step # 7).

  Regarding the provisional capacitance signal Ci in the (K-2) th and (K-1) th driving periods, there are positions where the difference in capacitance at each position in the detection plane P is equal to or greater than the threshold value L. This is a case where there is a steep change in capacitance at some positions in the detection surface P during the first drive period. That is, in this case, an apparent variation (in the calculation result) of the capacitance in the capacitance signal Ei as described above may occur. Therefore, in this case, the apparent variation (on the calculation result) is obtained by averaging the provisional capacitance signal Ci in the (K-1) th driving period and the provisional capacitance signal Ci in the Kth driving period. The capacitance signal Ei of the Kth driving period in which the above is suppressed is generated.

  As described above, in the touch panel system 1 according to the embodiment of the present invention, the capacitance at some positions in the detection surface P changes steeply during the driving period, so that it is not related to the position in the capacitance signal Ei. In the case where the capacity of the position may fluctuate (on the calculation result), the correction unit 33 averages the provisional capacity signal Ci when generating the capacity signal Ei, so that the appearance (on the calculation result) is obtained. To suppress fluctuations. Therefore, the detection accuracy of the indicator in the touch panel system 1 can be increased.

  In the touch panel system 1, two or more provisional capacitance signals Ci need to be stored in the storage unit 34 (K is 3 or more) at the time of performing steps # 3 and # 4 in FIG. Therefore, for example, until the two or more provisional capacitance signals Ci are stored in the storage unit 34, for example, the correction unit 33 may not output the capacitance signal Ei, or the provisional capacitance of the Kth drive period. The signal Ci may be output as it is as the capacitance signal Ei.

  Further, in step # 6 of FIG. 5, the provisional capacitance signal Ci in the (K-2) th driving period may be used as the capacitance signal Ei in the Kth driving period. However, detection of an indicator in the touch panel system 1 is more effective when the temporary capacitance signal Ci of the (K-1) th driving period, which is temporally closer to the current (Kth) driving period for which the capacitance signal Ei is to be obtained, is used. Can be performed quickly, which is preferable.

  Further, in step # 7 of FIG. 5, the provisional capacitance signal Ci in the K-2th to Kth driving periods may be averaged to generate the capacitance signal Ei. However, if the provisional capacitance signal Ci in the (K−1) -th and K-th driving periods after the start of the steep capacitance change is averaged, the steep capacitance change in the capacitance signal Ei is more effective. By reflecting, it becomes possible to improve the detection accuracy of the indicator in the touch panel system 1, which is preferable.

[Concrete example]
A specific example of a method for correcting the provisional capacitance signal Ci by the correction unit 33 will be described with reference to the drawings. FIG. 6 is a table showing a specific example of a provisional capacitance signal correction method (capacitance signal generation method) by the correction unit. In FIG. 6, specific examples of the in-plane distribution of the actual capacity, the in-plane distribution of the capacity indicated by the provisional capacity signal, and the in-plane distribution of the capacity indicated by the capacity signal can be compared. Shown side by side.

  The table shown in FIG. 6 corresponds to FIG. 3 and FIG. 4 and shows fluctuations in the four capacitors C11 to C41 formed by one sense line SL1 and four drive lines DL1 to DL4. Is. In the following, for simplification of description, it is assumed that the touch panel 10 includes only the sense line SL1 and the drive lines DL1 to DL4, and only the capacitors C11 to C41 are formed in the detection surface P.

  In the table shown in FIG. 6, the drive period Q1 is the drive period Q1 for the first to fourth drive of the drive line, the drive period Q2 is the drive period for the fifth to eighth drive, and the ninth to twelfth drive is the drive period Q2. The driving period Q3 is the driving period Q3, and the thirteenth to sixteenth driving periods are the driving periods Q4. In each driving period Q1 to Q4, the components of the drive signal shown in the lower table of FIG. Given to DL1-DL4, drive lines DL1-DL4 are driven.

  In the table shown in FIG. 6, the capacity when there is no indicator in contact with or close to the detection surface P is “10”, and the threshold value L is “2.5”. In addition, at the start of the driving period Q1, the provisional capacitance signal Ci stored in the storage unit 34 in the driving period two times before (K-2) and one time before (K-1) the driving period Q1. It is assumed that the capacitances C11 to C41 indicated by each are all “10”.

(Driving period Q1)
As shown in FIG. 6, in the driving period Q1, since there is no indicator that is in contact with or close to the detection surface P, the actual capacitors C11 to C41 during the first to fourth driving are all “10”. ing. In this case, the output values Cout11 to Cout41 of the sense line SL1 obtained by the above formulas (1) to (4) are as shown in the following calculation formula.

Cout11 = 10 + 10 + 10 + 10 = 40
Cout21 = 10−10 + 10−10 = 0
Cout31 = 10 + 10-10-10 = 0
Cout41 = 10-10-10 + 10 = 0

  Then, the capacitances C11 to C41 in the provisional capacitance signal Ci obtained by the above formulas (5) to (8) using the output values Cout11 to Cout41 are all “10” as shown in the following calculation formula and FIG. "become. The provisional capacity signal Ci is stored in the storage unit 34.

40 + 0 + 0 + 0 = 4 · C11 C11 = 10
40-0 + 0-0 = 4 · C21 C21 = 10
40 + 0-0-0 = 4 · C31 C31 = 10
40-0-0 + 0 = 4 · C41 C41 = 10

  As described above, the capacitances C11 to C41 indicated by the provisional capacitance signals Ci in the driving period immediately before (K−1) and two times before (K−2) the driving period Q1 are all “10”. is there. Therefore, the capacitors C11 to C41 indicated by the provisional capacitance signal Ci in the driving period immediately before the driving period Q1 (K−1) and the provisional capacity in the driving period two times before (K−2) in the driving period Q1. The differences from the capacitors C11 to C41 indicated by the signal Ci are all “0”, which is smaller than the threshold L “2.5”.

  Therefore, the correction unit 33 outputs the provisional capacitance signal Ci of the driving period immediately before the driving period Q1 (K−1th) as the capacitance signal Ei of the driving period Q1. Therefore, the capacitors C11 to C41 indicated by the capacitance signal Ei in the driving period Q1 are all “10”.

(Driving period Q2)
As shown in FIG. 6, in the driving period Q2, as in the driving period Q1, there is no indicator that is in contact with or close to the detection surface P, so that the actual capacitances C11 to C41 at the fifth to eighth driving are , All are "10". In addition, the capacitors C11 to C41 indicated by the provisional capacitance signals Ci stored in the storage unit 34 in the driving period two times before (K-2) and one time before (K-1) the driving period Q2, respectively. Are all “10”.

  Therefore, in the driving period Q2, the same operation as that in the driving period Q1 described above is performed. That is, in the driving period Q2, the provisional capacitance signal Ci in which the capacitors C11 to C41 are all “10” is stored in the storage unit 34, and the capacitor signal Ei in which the capacitors C11 to C41 are all “10” is generated.

(Driving period Q3)
As shown in FIG. 6, in the driving period Q3, the indicator is in contact with or close to the detection surface P in the middle of the driving period Q3. Therefore, the size of the capacitor C31 is changed from “10” to “4” during the driving period. Has decreased. In this case, the output values Cout11 to Cout41 of the sense line SL1 obtained by the above formulas (1) to (4) are as shown in the following calculation formula.

Cout11 = 10 + 10 + 10 + 10 = 40
Cout21 = 10−10 + 10−10 = 0
Cout31 = 10 + 10-4-10 = 6
Cout41 = 10−10−4 + 10 = 6

  And the capacity | capacitance C11-C41 which the temporary capacity | capacitance signal Ci calculated | required by said Formula (5)-(8) using this output value Cout11-Cout41 is as the following calculation formulas and FIG. The provisional capacity signal Ci is stored in the storage unit 34.

40 + 0 + 6 + 6 = 4 · C11 C11 = 13
40-0 + 6-6 = 4 · C21 C21 = 10
40 + 0-6-6 = 4 · C31 C31 = 7
40-0-6 + 6 = 4 · C41 C41 = 10

  As shown in FIG. 6, in the example of the driving period Q3, the temporary capacity signal Ci has a value larger than “10” even though the actual capacity C11 remains “10” throughout the driving period Q3. It is “13”. Thus, if the capacitance C31 at a part of the position in the detection surface P changes steeply during the driving period Q3, not only the calculation result of the capacitance C31 at the position changes, but also other values unrelated to the position. The calculation result of the position capacitance C11 may vary.

  Similarly to the driving periods Q1 and Q2, in the driving period Q3, the capacitances C11 to C41 indicated by the provisional capacitance signals Ci of the two previous (K-2th) and the previous (K-1th) driving periods are as follows. All are “10”, and all the differences are “0”. For this reason, the capacitance difference indicated by the provisional capacitance signal Ci is smaller than “2.5” of the threshold value L at all positions in the detection surface P, and the correction unit 33 is immediately before the driving period Q3 (K The provisional capacitance signal Ci in the (−1) th driving period is output as the capacitance signal Ei in the driving period Q3. Therefore, the capacitors C11 to C41 indicated by the capacitance signal Ei in the driving period Q3 are all “10”.

(Driving period Q4)
As shown in FIG. 6, in the driving period Q4, the indicator C is in contact with or close to the detection surface P following the driving period Q3, and thus the size of the capacitor C31 is “4”. In this case, the output values Cout11 to Cout41 of the sense line SL1 obtained by the above formulas (1) to (4) are as shown in the following calculation formula.

Cout11 = 10 + 10 + 4 + 10 = 34
Cout21 = 10-10 + 4-10 = -6
Cout31 = 10 + 10-4-10 = 6
Cout41 = 10−10−4 + 10 = 6

  And the capacity | capacitance C11-C41 which the temporary capacity | capacitance signal Ci calculated | required by said Formula (5)-(8) using this output value Cout11-Cout41 is as the following calculation formulas and FIG. The provisional capacity signal Ci is stored in the storage unit 34.

34 + (− 6) + 6 + 6 = 4 · C11 C11 = 10
34 − (− 6) + 6−6 = 4 · C21 C21 = 10
34 + (− 6) −6−6 = 4 · C31 C31 = 4
34 − (− 6) −6 + 6 = 4 · C41 C41 = 10

  In the driving period Q4, the capacitors C11 to C41 indicated by the provisional capacitance signal Ci in the second previous (K-2th) driving period are all “10”, but in the previous driving period (K−1th). The capacitors C11 to C41 indicated by the provisional capacitor signal Ci have the capacitor C11 of “13”, the capacitor C21 of “10”, the capacitor C31 of “7”, and the capacitor C41 of “10” (in the drive period Q3 in FIG. 6). Provisional capacity signal Ci). For these provisional capacitance signals Ci, for example, since the difference of the capacitance C11 is “3”, there is a position where the threshold value L is “2.5” or more.

  In this case, the correction unit 33 averages the provisional capacitance signal Ci in the previous (K−1) th driving period and the provisional capacitance signal Ci in the current (Kth) driving period, thereby obtaining K A capacitance signal Ei for the first driving period is generated. The capacitances C11 to C41 indicated by the generated capacitance signal Ei are as shown in the following calculation formula and FIG.

C11 = (10 + 13) /2=11.5
C21 = (10 + 10) / 2 = 10
C31 = (7 + 4) /2=5.5
C41 = (10 + 10) / 2 = 10

  As described above, the capacitance C31 at some positions in the detection surface P steeply changes during the driving period Q3, so that the capacitance at a position unrelated to the position in the capacitance signal Ei appears (calculation result). (Upper) In the case where the fluctuation can occur, the correction unit 33 averages the provisional processing results Ci of the driving periods Q3 and Q4 to generate the capacitance signal Ei, thereby making the apparent (calculation result) in the capacitance C11 in the capacitance signal Ei. Suppress fluctuations in (above). Therefore, the detection accuracy of the indicator in the touch panel system 1 can be increased.

<< M series >>
So far, the case of using an orthogonal sequence as a component of a drive signal has been described, but an M sequence that is a pseudo-orthogonal sequence may be used. That is, the matrix “H” which is a component of the drive signal is applied with an M-sequence code having a code length N (= 2 ⁿ −1) in the first row, and the code obtained by sequentially shifting the bit by 1 bit after the second row. It is good also as what applied. Also in this case, the matrix “C” (that is, the in-plane distribution of the capacity) can be obtained only by obtaining the inner product of the transposed matrix “H ^T ” of “H” and the matrix “Cout”. However, unlike the case of using an orthogonal sequence, an error is included in the inner product calculation result when an M sequence is used. However, by increasing the code length N such as N = 63 or 127, the degradation of the SN ratio is suppressed. It is possible.

<< Electronic Information Equipment >>
A configuration example of the electronic information device according to the embodiment of the present invention including the touch panel system 1 described above will be described with reference to FIG. FIG. 7 is a block diagram illustrating a configuration example of the electronic information device according to the embodiment of the present invention.

  As shown in FIG. 7, an electronic information device 100 according to an embodiment of the present invention includes a display device 101, a display device control unit 102 that controls the display device 101, a touch panel 103 corresponding to the touch panel 10 described above, Touch panel controller 104 corresponding to each part (drive line drive unit 20, sense signal processing unit 30, indicator position detection unit 40, clock signal generation unit 50, and touch panel control unit 60) except touch panel 10 in touch panel system 1 of FIG. A button switch unit 105 that accepts a user instruction when pressed by the user, an imaging unit 106 that generates image data by imaging, an audio output unit 107 that outputs input audio data as audio, and an audio by collecting sound A sound collecting unit 108 that generates data and a sound to be given to the sound output unit 107 A voice processing unit 109 that performs processing of data and processing of voice data given from the sound collection unit 108, a wireless communication unit 110 that wirelessly communicates communication data with devices external to the electronic information device 100, and a wireless communication unit 110 Radiates communication data communicated by radio as an electromagnetic wave, and receives an electromagnetic wave radiated from a device external to the electronic information device 100, and wired communication that communicates communication data with a device external to the electronic information device 100 by wire. A communication unit 112, a memory 113 that stores various data, and a main body control unit 114 that controls the overall operation of the electronic information device 100 are provided.

  Note that some or all of the correction unit 33, the indicator position detection unit 40, the clock signal generation unit 50, and the touch panel control unit 60 described above may be part of the main body control unit 114 instead of the touch panel controller 104. Similarly, the storage unit 34 described above may be a part of the memory 113 instead of the touch panel controller 104.

  Further, the electronic information device 100 illustrated in FIG. 7 is only one application example of the touch panel system 1. The touch panel system 1 described above can be applied to an electronic information device having a configuration different from that of the electronic information device 100.

<< Deformation, etc. >>
[1] The above-mentioned threshold value L prevents the averaging of the provisional capacitance signal Ci (step # 5, YES and step # 7 in FIG. 5) from being performed excessively or conversely. It is preferable that the touch panel system 1 can be changed according to the characteristics, application, usage environment, and the like. Specifically, for example, it is preferable that the storage unit 34 stores a plurality of values that the threshold L can take, and the threshold L is switched by an automatic or manual method.

[2] The correction method of the provisional capacitance signal Ci by the correction unit 33 shown in FIG. 5 compares the difference between the provisional capacitance signal Ci in the K-2th and K-1th drive periods with the threshold L (FIG. 5). Steps # 3 to # 5), if there is no position where the difference is equal to or larger than the threshold (Step # 5, NO), the provisional capacitance signal Ci in the (K-1) th drive period is set as the capacitance signal Ei (Step # 6). If there is a position equal to or greater than the threshold (step # 5, YES), the provisional capacitance signal Ci for the (K-1) th and Kth drive periods is averaged to generate the capacitance signal Ei (step # 7).

  In the correction method of the provisional capacitance signal Ci, the provisional capacitance signal Ci in the past driving period to be used may be different from the method shown in FIG. Specifically, for example, the correction unit 33 may generate the capacity signal Ei by correcting the provisional capacity signal Ci by the following correction method.

  In this provisional capacitance signal Ci correction method, first, the correction unit 33 acquires the provisional capacitance signal Ci for the Kth drive period (corresponding to step # 1 in FIG. 5), and the storage unit 34 stores the Kth. The provisional capacitance signal Ci for the driving period is stored (corresponding to step # 2 in FIG. 5). Next, the correction unit 33 obtains a difference in capacitance at the same position in the detection plane P for the provisional capacitance signal Ci in the (K−X) th and (K−X + 1) th driving periods, and compares it with a threshold value L (FIG. 5 steps # 3 to # 5). If there is no position in the detection surface P where the difference is equal to or greater than the threshold value L (corresponding to step # 5, NO), the correction unit 33 uses the provisional capacitance signal Ci for the (K−X + 1) th driving period as the capacitance signal. Ei (corresponding to step # 6). On the other hand, if there is a position in the detection surface P where the difference is equal to or greater than the threshold value L (corresponding to YES at step # 5), the correcting unit 33 provisional capacity signal Ci for the (K−X + 1) th to Kth driving periods. Are averaged to generate a capacitance signal Ei (corresponding to step # 7).

  X is a natural number greater than or equal to 2 and less than K. X represents the number of provisional capacitance signals Ci to be averaged in a step corresponding to step # 7 in FIG. Note that the flowchart shown in FIG. 5 is for X = 2.

  As the value of X is increased, the number of provisional capacitance signals Ci to be averaged increases, so that it is possible to effectively suppress the fluctuation of the apparent capacity (on the calculation result). However, since the provisional capacitance signal Ci in a driving period that is far in time from the current (Kth) driving period is used, an abrupt change in actual capacitance clearly appears in the capacitance signal Ei (indicator position detection). There is a possibility that the time difference until the indicator can be detected in the unit 40 becomes large. Therefore, when these are comprehensively weighed, it can be said that X is preferably set to 3 or less.

  Further, similarly to the threshold value L described in the modified example of [1], it is preferable that X can be changed according to the characteristics, application, use environment, and the like of the touch panel system 1. Specifically, for example, it is preferable that the storage unit 34 stores a plurality of values that X can take and the value of X can be switched automatically or manually.

  Note that the correction unit 33 does not compare the provisional capacitance signals Ci of two consecutive drive periods in the steps corresponding to steps # 3 to # 5 in FIG. 5, but provisionally of three or more consecutive drive periods. The capacitance signal Ci may be compared. Specifically, for example, the correction unit 33 obtains the difference between the maximum value and the minimum value of the capacitance at the same position in the detection surface P for the provisional capacitance signal Ci of three or more consecutive drive periods, The threshold value L may be compared.

  Further, the averaging of the provisional capacity signal Ci performed by the correction unit 33 may be a simple average or a weighted average.

[3] As the touch panel system 1 according to the embodiment of the present invention, an example is shown in which the provisional capacitance signal Ci is averaged as necessary to generate the capacitance signal Ei, but the capacitance signal Ei is apparently (on the calculation result). From the viewpoint of suppressing fluctuations in capacitance, it is only necessary to average the processing results of the sense signal Si, and the target of averaging is not necessarily limited to the provisional capacitance signal Ci. Specifically, for example, even when the output value Cout (see FIG. 3) indicated by the post-processing signal Ai is averaged, it is possible to suppress a change in the apparent capacity (on the calculation result).

  A touch panel system that averages the output value Cout indicated by the processed signal Ai will be described with reference to FIG. FIG. 8 is a block diagram showing an example of the overall structure of a touch panel system according to another embodiment of the present invention. 8 is different from the touch panel system 1 shown in FIG. 1 only in the sense signal processing units 30 and 30a. Therefore, only the sense signal processing unit 30a of the touch panel system 1a will be described here, and the description of the other parts will be omitted because the description related to the touch panel system 1 is referred to.

  As shown in FIG. 8, the sense signal processing unit 30a of the touch panel system 1a includes a sense signal acquisition unit 31, a decoding processing unit 32, a correction unit 33a, and a storage unit 34a.

  The sense signal acquisition unit 31 acquires a sense signal Si appearing on the sense line SL at a predetermined timing according to control by the touch panel control unit 60, and generates a post-provisional signal Bi by performing processing such as amplification and conversion. . The correction unit 33a corrects the provisional post-processing signal Bi obtained from the sense signal acquisition unit 31, thereby generating the post-processing signal Ai. The storage unit 34a sequentially stores the post-provisional signal Bi generated sequentially by the sense signal acquisition unit 31. The decoding processing unit 32 generates the capacitance signal Ei by decoding the post-processing signal Ai generated by the correction unit 33a according to the control by the touch panel control unit 60.

  The correction method of the post-provisional signal Bi in the correction unit 33a is the same as the correction method (see FIG. 5) of the temporary capacitance signal Ci in the correction unit 33 of the touch panel system 1 described above. Specifically, for example, the correction unit 33a may correct the post-provisional signal Bi by a correction method described below.

  In this method for correcting the post-provisional signal Bi, first, the correction unit 33a acquires the post-provisional signal Bi for the Kth drive period (corresponding to step # 1 in FIG. 5), and the storage unit 34a Stores the post-provisional signal Bi for the first drive period (corresponding to step # 2 in FIG. 5). Next, the difference between the output values Cout obtained by the correction unit 33a processing the sense signal Si acquired from the same sense line SL for the provisionally processed signal Bi in the K-2th and K-1th drive periods. Are respectively compared with a predetermined threshold (corresponding to steps # 3 to # 5 in FIG. 5). Then, if there is no sense line SL in which the difference is equal to or greater than the threshold (corresponding to step # 5, NO), the correction unit 33a uses the post-processing signal Bi as the post-processing signal Ai for the (K-1) th driving period. (Corresponding to step # 6). On the other hand, if there is a sense line SL in which the difference is equal to or greater than the threshold (corresponding to step # 5, YES), the correction unit 33a averages the post-provisional signal Bi for the (K-1) th and Kth drive periods. Then, a post-processing signal Ai is generated (corresponding to step # 7).

  Note that the modification [2] is naturally applicable to this modification. That is, the correction unit 33a may generate the post-processing signal Ai by averaging two or more provisional post-processing signals Bi as necessary.

[4] Although FIG. 6 illustrates the case where continuous drive periods Q1 to Q4 do not overlap at all, these drive periods may partially overlap. Specifically, for example, in the example illustrated in FIG. 6, the second to fifth driving periods may be subsequent to the first to fourth driving periods Q1. In this case, each time the drive lines DL1 to DL4 are driven once, a new optimized capacitance signal Ei can be obtained. Therefore, the number of detections of the indicator is increased (detection of the indicator is performed densely). Is possible.

<< Summary >>
The touch panel systems 1 and 1a and the electronic information device 100 according to the embodiment of the present invention can be grasped as follows, for example.

  The touch panel system 1, 1 a according to the embodiment of the present invention includes a plurality of drive lines DL provided in parallel with each other along the detection surface P, and provided with the drive lines DL in parallel with each other along the detection surface P. A touch panel 10 including a plurality of intersecting sense lines SL, a drive line driving unit 20 that is driven by sequentially supplying a drive signal Di that varies to the plurality of drive lines DL, and the drive lines DL are made a predetermined number of times. Capacitance signal indicating the in-plane distribution of the capacitance C formed by the drive line DL and the sense line SL by sequentially obtaining and processing the sense signal Si appearing on the sense line SL during the driving period, which is a driving period. Based on the sense signal processing unit 30 for generating Ei and the capacitance signal Ei, the touch panel An indicator position detector 40 that detects the position of the indicator that is in contact with or close to the ten detection surfaces P, and the sense signal processor 30 generates the capacitance signal Ei in the target drive period. In this case, the processing result of the sense signal Si obtained in the driving period before the driving period of interest is compared for a plurality of consecutive predetermined driving periods, and the plurality of the processing results compared are When the capacitance signal Ei in the driving period of the target is generated when the deviation exceeds a predetermined reference, the sense signal Si obtained in the driving period before the driving period of the target The processing result is averaged over a plurality of consecutive predetermined driving periods.

  In the touch panel systems 1 and 1a, the capacitance at a part of the detection surface P in the detection surface P rapidly changes during the driving period, so that the capacitance at a position unrelated to the position in the provisional capacitance signal Ci is apparently ( In the case where the fluctuation may occur (on the calculation result), the sense signal processing unit 30 suppresses the apparent fluctuation (on the calculation result) by averaging the processing results when generating the capacitance signal Ei. Therefore, the detection accuracy of the indicator in the touch panel system 1 or 1a can be increased.

  Furthermore, when the touch panel system 1 or 1a has a natural number of 2 or more and K is a natural number larger than X, the sense signal processing unit 30 generates the capacitance signal Ei in the Kth driving period. In this case, the processing result of the sense signal Si obtained in the K-Xth driving period is compared with the processing result of the sense signal Si obtained in the K-X + 1th driving period. When the compared two processing results deviate beyond a predetermined reference, when generating the capacitance signal Ei in the Kth driving period, the driving from K−X + 1 to Kth The processing result of the sense signal Si obtained in the period is averaged.

  In the touch panel systems 1 and 1a, when there is a sudden change in capacitance at some positions in the detection plane P during the XXth and XX + 1th drive periods, that is, in the capacitance signal Ei. In the case where the apparent variation (in the calculation result) of the capacitance can occur, the sense signal Si obtained in the K-X + 1th to Kth driving periods after the sudden capacitance variation is started. By averaging the processing results, the capacitance signal Ei for the Kth driving period in which the apparent fluctuation (on the calculation result) is suppressed is generated. As a result, the steep capacitance variation is effectively reflected in the capacitance signal Ei, so that the detection accuracy of the indicator in the touch panel systems 1 and 1a can be increased.

  Furthermore, when the touch panel system 1 or 1a has a natural number of 2 or more and K is a natural number larger than X, the sense signal processing unit 30 generates the capacitance signal Ei in the Kth driving period. In this case, the processing result of the sense signal Si obtained in the K-Xth driving period is compared with the processing result of the sense signal Si obtained in the K-X + 1th driving period. When the two processed results compared do not deviate beyond a predetermined reference, the K−X + 1th driving period is obtained when the capacitance signal Ei in the Kth driving period is generated. Further, the processing result of the sense signal Si is used.

  In the touch panel systems 1 and 1a, when there is no sudden change in the capacitance over the entire detection surface P during the (KX) th and (KX + 1) th drive periods, that is, the apparent capacitance appears in the capacitance signal Ei. In the case where fluctuations (on the calculation result) cannot occur, the capacity of the Kth driving period is calculated using the processing result of the (K−1) th driving period that is temporally close to the current (Kth) driving period. It becomes possible to generate the signal Ei.

  Further, in the touch panel system 1, 1a, the X is 3 or less.

  In the touch panel systems 1 and 1a, the apparent change in the capacitance signal Ei (on the calculation result) is effectively suppressed, and a steep change in the actual capacitance is clearly shown in the capacitance signal Ei (indicator position). The time difference until the indicator can be detected by the detection unit 40 can be reduced.

  Further, in the touch panel system 1, the drive line DL and the sense line SL are generated as the processing result is generated by the sense signal processing unit 30 processing the sense signal Si obtained in one drive period. Is a provisional capacitance signal Ci indicating the in-plane distribution of the capacitance C formed by In this case, the sense signal processing unit 30 compares the capacitance C at the same position in the detection surface P indicated by the provisional capacitance signal Ci.

  Alternatively, the touch panel system 1a generates a signal of each of the sense signals Si, which is generated when the processing result is processed by each of the sense signals Si appearing on each of the sense lines SL by the sense signal processing unit 30. This is a post-provisional signal Bi indicating a value. In this case, the sense signal processing unit 30 compares the signal value of the sense signal Si obtained from the same sense line SL indicated by the provisional post-processing signal Bi.

  In any of the touch panel systems 1 and 1a, since the processing result of the sense signal Si is not changed, it is possible to suppress a change in apparent capacitance (on the calculation result) of the capacitance signal Ei. is there.

  Furthermore, in the touch panel systems 1 and 1a, the components of the drive signal Di given to the plurality of drive lines DL are orthogonal sequences or M sequences.

In the touch panel system 1, 1 a, the capacitance in-plane is simply calculated by calculating the inner product of the transposed matrix “H ^T ” composed of the components of the drive signal Di and the matrix “Cout” composed of the output value of the sense signal. Distribution can be obtained.

  The electronic information device 100 according to the embodiment of the present invention includes the touch panel systems 1 and 1a.

  The present invention can be suitably used for a touch panel system including a large touch panel, a touch panel system in which a quick operation by a user is performed, and an electronic information device including these touch panel systems.

1: Touch panel system 10: Touch panel 20: Drive line drive unit 30: Sense signal processing unit 31: Sense signal acquisition unit 32: Decoding processing unit 33: Correction unit 34: Storage unit 40: Indicator position detection unit 50: Clock signal generation Unit 60: touch panel control unit 100: electronic information device DL: drive line SL: sense line P: detection surface Di: drive signal Si: sense signal Ai: post-processing signal Ci: provisional capacity signal Ei: capacity signal Bi: after provisional processing signal

Claims (5)

A touch panel comprising a plurality of drive lines provided parallel to each other along the detection surface, and a plurality of sense lines provided parallel to each other along the detection surface and intersecting the drive lines;
A drive line drive unit that is driven by giving a drive signal that sequentially changes to the plurality of drive lines;
A capacitance indicating an in-plane distribution of capacitance formed by the drive line and the sense line by sequentially acquiring and processing sense signals appearing on the sense line during a drive period in which the drive line is driven a predetermined number of times. A sense signal processing unit for generating a signal;
An indicator position detection unit that detects a position of an indicator that is in contact with or close to the detection surface of the touch panel based on the capacitance signal;
The sense signal processor is
When generating the capacitance signal in the target driving period, the processing result of the sense signal obtained in the driving period before the target driving period is compared for a plurality of consecutive predetermined driving periods. And
When the plurality of processing results compared are deviating beyond a predetermined standard,
When generating the capacitance signal in the driving period of the target, the processing result of the sense signal obtained in the driving period that is before the driving period of the target is converted into a predetermined number of the driving periods. A touch panel system characterized by averaging. When X is a natural number of 2 or more and K is a natural number larger than X,
The sense signal processor is
When generating the capacitance signal in the Kth drive period, the processing result of the sense signal obtained in the KX drive period and the KX + 1 drive period are obtained. Compare the processing result of the sense signal,
When the two processing results compared with each other deviate beyond a predetermined standard,
The said processing result of the said sense signal obtained in the said drive period from the K-X + 1st to the Kth is averaged when producing | generating the said capacity | capacitance signal in the said Kth drive period. The touch panel system according to 1. When X is a natural number of 2 or more and K is a natural number larger than X,
The sense signal processor is
When generating the capacitance signal in the Kth drive period, the processing result of the sense signal obtained in the KX drive period and the KX + 1 drive period are obtained. Compare the processing result of the sense signal,
If the two processing results compared do not deviate beyond a predetermined standard,
3. The process according to claim 1, wherein the processing result of the sense signal obtained in the (K−X + 1) th driving period is used when generating the capacitance signal in the Kth driving period. 4. Touch panel system.   The provisional capacitance indicating the in-plane distribution of the capacitance formed by the drive line and the sense line, which is generated by processing the sense signal obtained by the sense signal processing unit in one drive period, by the processing result. It is a signal, The touch panel system of any one of Claims 1-3 characterized by the above-mentioned.   The processing result is a post-provisional signal indicating a signal value of each sense signal generated by the sense signal processing unit processing each sense signal appearing on each sense line. The touch panel system according to any one of claims 1 to 3.

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