JP6410699B2 - Input device, input device control method, and program for causing computer to execute input device control method - Google Patents

Description

  The present invention relates to an input device, an input device control method, and a program that causes a computer to execute the input device control method.

  There is an input device that detects a proximity state of an operating body such as a finger by measuring physical quantities such as capacitance at a plurality of detection positions in a detection region. An input device as an example includes a plurality of parallel drive electrodes arranged in one layer and a plurality of parallel detection electrodes arranged in another layer, and the intersection position of the drive electrode and the detection electrode is determined. The detection position.

  There is an encoding drive as a driving method for acquiring the capacitance at a plurality of detection positions. In the encoding drive, for example, a drive signal having a positive or negative polarity is simultaneously applied to a plurality of drive electrodes. The signal output via the detection electrode is the sum (composite detection signal) of the capacitance detection signals at the respective detection positions. This combined detection signal is repeatedly measured by the number of detection positions (the number of drive electrodes) while changing the polarity pattern of the drive signal. Then, the electrostatic capacitance at each detection position is calculated based on the obtained plurality of combined detection signals and the polarity pattern of the drive signal.

International Publication No. 2009/107415 Special table 2013-501996 gazette

  In encoding driving, the product of a composite detection signal matrix obtained by a plurality of measurements and an inverse matrix derived from the driving matrix representing the polarity pattern of the driving signal is calculated to obtain a static signal at each detection position. The capacity is calculated. Since the calculation of the matrix product is very heavy, it is desirable to select the driving matrix so that the calculation is as simple as possible. Therefore, in Patent Documents 1 and 2 described above, a method using a Hadamard matrix or a modified matrix thereof as a driving matrix is studied.

  In the encoding drive, it is desirable to make the number of positive drive signals and the number of negative drive signals applied simultaneously to a plurality of drive electrodes as close as possible to each other in the measurement of one detection signal. As a result, the level of the combined detection signal (the sum of the detection signals) is reduced, so that it is easy to increase the detection sensitivity in the circuit that processes the combined detection signal. In addition, by balancing the number of positive drive signals and the number of negative drive signals, the electric field due to the drive signals is canceled and reduced, and the total radiation noise is reduced. Therefore, when selecting a drive matrix, it is necessary to consider that the number of positive drive signals and negative drive signals applied simultaneously to a plurality of drive electrodes is approximately the same.

  Furthermore, several methods such as the Sylvester method and the Paley method are known as Hadamard matrix generation methods, but each generation method has a limitation on the order of the matrix. For example, the order of the Hadamard matrix by the Sylvester method is limited to a power of 2. Therefore, the number of drive electrodes to which the drive signal is applied simultaneously in one measurement, that is, the number of detection positions from which the detection signal that is the source of the combined detection signal (the sum of the detection signals) is obtained depends on the order of the drive matrix. Limited. If the number of detection positions is too small, it becomes difficult to obtain a desired resolution. Conversely, if the number of detection positions is too large, power consumption and radiation noise increase due to use of a useless drive signal is likely to occur. Therefore, in encoding driving, it is required to increase variations in the number of detection positions where each detection signal can be calculated from the combined detection signal (the sum of detection signals).

  The present invention has been made in view of such circumstances, and an object of the present invention is to calculate an original detection signal from the sum of detection signals at a plurality of detection positions where the proximity state of an object is detected. An input device, a method for controlling the input device, and a method for controlling the input device in a computer can be used to reduce the number of detection positions where the original detection signal can be calculated from the sum of the detection signals. It is to provide a program to be executed.

  The 1st viewpoint of the present invention is related with the input device which inputs the information according to the proximity state of the object in a plurality of detection positions. The input device includes a sensor unit, a control unit, and a signal reproduction unit. The sensor unit detects at least one proximity state of the object at the group of detection positions, and generates at least one detection unit that generates a combined detection signal corresponding to the sum of the group of detection signals obtained as a result of the detection for the group of detection positions. The polarity of the detection signal having a signal level corresponding to the proximity state can be controlled at each detection position. The control unit is a group of combined detection signals composed of combined detection signals in which the polarity patterns that are a group of polarities set to the group of detection signals are different from each other, and the group of the same number of combined detection signals as the group of detection signals The sensor unit is controlled so that the combined detection signal is generated in the detection unit. The signal reproducing unit reproduces the signal level of the group of detection signals that are the basis of the combined detection signal based on the group of combined detection signals generated by the detection unit. A group of detection positions in one detection unit is N, and positive or negative polarity set in the detection signal is represented by “1” or “−1” and set for a detection signal that is not added to the combined detection signal. The polarity to be displayed is represented by “0”, and the polarity pattern set to a group of detection signals composed of N detection signals is one row having one of the elements “1”, “−1”, and “0”. In the case where a group of polarity patterns consisting of N polar patterns and a group of N polar patterns are represented by a matrix of N rows and N columns consisting of N partial matrices, the signal reproducing unit An extended inverse matrix in which one of an element greater than “0” and an element less than “0” in the inverse matrix for a column is replaced with “1” and the other is replaced with “−1”; Combining N rows and 1 column with a group of composite detection signals generated by one detector as elements The operation corresponding to the signal matrix output, the product, generates a reproduction signal level matrix of N rows and one column. The matrix of N rows and N columns includes a first partial matrix of 1 row and N columns and a second partial matrix of (N−1) rows and N columns. The first submatrix has one element that is “1” or “−1” and (N−1) elements that are “0”. In the second submatrix, the sum of the elements in any row is “0”. The second submatrix has a main submatrix that is a submatrix with (N-1) rows (N-1) columns. In the main submatrix, the sum of the elements in any row is “1” or “−1”.

According to this configuration, the first sub-matrix having 1 row and N columns in the matrix having N rows and N columns includes one element that is “1” or “−1” and (N−1) elements that are “0”. Therefore, the sum of the elements in the row is “1” or “−1”. In the second submatrix of (N−1) rows and N columns in the N rows and N columns matrix, the sum of the elements in any row is “0”. That is, the sum of the elements in each row in the N × N matrix is “1” or “−1” at the maximum. Therefore, the number of positive polarity and the number of negative polarity included in each polarity pattern are approximated, and the difference between the number of positive polarity detection signals and the number of negative polarity detection signals that are the basis of the combined detection signal is small. Thereby, compared with the case where the balance of the number of detection signals is biased to one polarity, the signal level of the combined detection signal is reduced. When the signal level of the combined detection signal decreases, the signal reproduction unit that inputs the combined detection signal can sufficiently secure the dynamic range of the combined detection signal. Playback with high sensitivity becomes possible. Further, since the difference between the number of positive detection signals and the number of negative detection signals is reduced, radiation noise caused by the detection signals is reduced.
Further, only (N−1) detection signals are obtained by using only a main submatrix (for example, a Hadamard matrix by the Paley method or a modified matrix thereof) which is a submatrix of (N−1) rows (N−1) columns. Compared to the case where the signal level is reproduced, the number of reproducible detection signals is increased by one. This increases variations in the number of detection positions where the original detection signal can be calculated from the combined detection signal (the sum of the detection signals).

  Preferably, the control unit may divide the reproduction signal level matrix by a predetermined correction coefficient to generate a corrected correction signal level matrix.

  A second aspect of the present invention relates to an input device that inputs information according to the proximity state of an object at a plurality of detection positions. The input device includes a sensor unit, a control unit, and a signal reproduction unit. The sensor unit detects at least one proximity state of the object at the group of detection positions, and generates at least one detection unit that generates a combined detection signal corresponding to the sum of the group of detection signals obtained as a result of the detection for the group of detection positions. The polarity of the detection signal having a signal level corresponding to the proximity state can be controlled at each detection position. The control unit is a group of combined detection signals composed of combined detection signals in which the polarity patterns that are a group of polarities set to the group of detection signals are different from each other, and the group of the same number of combined detection signals as the group of detection signals The sensor unit is controlled so that the combined detection signal is generated in the detection unit. The signal reproducing unit reproduces the signal level of the group of detection signals that are the basis of the combined detection signal based on the group of combined detection signals generated by the detection unit. A group of detection positions in one detection unit is N, and positive or negative polarity set in the detection signal is represented by “1” or “−1” and set for a detection signal that is not added to the combined detection signal. The polarity to be displayed is represented by “0”, and the polarity pattern set to a group of detection signals composed of N detection signals is one row having one of the elements “1”, “−1”, and “0”. In the case where a group of polarity patterns consisting of N polar patterns and a group of N polar patterns are represented by a matrix of N rows and N columns consisting of N partial matrices, the signal reproducing unit An extended inverse matrix in which one of an element greater than “0” and an element less than “0” in the inverse matrix for a column is replaced with “1” and the other is replaced with “−1”; Combining N rows and 1 column with a group of composite detection signals generated by one detector as elements The operation corresponding to the signal matrix output, the product, generates a reproduction signal level matrix of N rows and one column. The matrix of N rows and N columns includes an intermediate submatrix of M rows and M columns. The intermediate submatrix includes a first submatrix with 1 row and M columns, and a second submatrix with (M−1) rows and M columns. The first submatrix has one reference element that is “1” or “−1” and (M−1) elements that are “0”. In the second submatrix, the sum of the elements in any row is “0”. The second submatrix has a main submatrix that is a submatrix with (M−1) rows (M−1) columns. In the main submatrix, the sum of the elements in any row is “1” or “−1”. Of the N-row N-column matrix, each of the 1-row N-column sub-matrices that do not overlap the intermediate sub-matrix is “1” or “−1” and “0” (N− 1) All N-by-1 sub-matrices that have one element and do not overlap the intermediate sub-matrix are each one element that is “1” or “−1” and “0” (N− 1) It has an element.

According to this configuration, among the N rows and N columns, all the 1 row and N column sub-matrices that do not overlap the M and M intermediate sub-matrices are each “1” or “−1”. And (N−1) elements that are “0”. Therefore, the sum of the elements in each row that does not overlap with the intermediate submatrix in the N-by-N matrix is “1” or “−1”.
In addition, among the N rows and N columns matrix, all the N rows and 1 column sub-matrices that do not overlap with the M rows and M columns of the intermediate sub-matrix each have one element that is “1” or “−1”, “ (N−1) elements that are “0”. Therefore, in all the N-row and 1-column sub-matrices, the element of the row overlapping the intermediate sub-matrix is “0”. Furthermore, the first submatrix with 1 row and M columns in the intermediate submatrix with M rows and M columns includes one element that is “1” or “−1” and (M−1) elements that are “0”. Therefore, the sum of the elements in the row is “1” or “−1”. In the second submatrix of (M−1) rows and M columns in the intermediate submatrix of M rows and M columns, the sum of the elements in any row is “0”. That is, the sum of the elements in each row in the M × M intermediate submatrix is “1” or “−1” at the maximum. Therefore, in the N-row N-column matrix, the sum of the elements of the rows overlapping the M-by-M intermediate submatrix is “1” or “−1” at the maximum.
As described above, since the sum of the elements of each row in the N-row N-column matrix is “1” or “−1” at the maximum, the number of positive polarity and the number of negative polarity included in each polarity pattern are approximated. The difference between the number of positive detection signals and the number of negative detection signals that are the basis of the combined detection signal is small. Thereby, compared with the case where the balance of the number of detection signals is biased to one polarity, the signal level of the combined detection signal is reduced. When the signal level of the combined detection signal decreases, the signal reproduction unit that inputs the combined detection signal can sufficiently secure the dynamic range of the combined detection signal. Playback with high sensitivity becomes possible. Further, since the difference between the number of positive detection signals and the number of negative detection signals is reduced, radiation noise caused by the detection signals is reduced.
Further, only (M−1) rows (M−1) columns of the main submatrix (for example, the Hadamard matrix by the Paley method or a modified matrix thereof) are used to generate (M−1) detection signals. Compared with the case where the signal level is reproduced, the number of detection signals that can be reproduced increases by (N−M + 1). This increases variations in the number of detection positions where the original detection signal can be calculated from the combined detection signal (the sum of the detection signals).

  Preferably, in the N-row N-column matrix, all 1-row N-column sub-matrices that do not overlap the intermediate sub-matrix may be located on the same side with respect to the main sub-matrix.

  Preferably, in the N-row and N-column matrix, some 1-row N-column sub-matrices that do not overlap the intermediate sub-matrix and other 1-row N-column sub-matrices are on different sides of the main sub-matrix May be located.

  Preferably, in the N × N matrix, all elements other than the intermediate submatrix other than “0” may be arranged on one diagonal line.

  Preferably, in an N × N matrix, elements other than the intermediate submatrix that are not “0” may be all “1” or all may be “−1”.

  Preferably, in the input device according to the second aspect of the present invention, the control unit divides an element corresponding to the intermediate submatrix in the reproduction signal level matrix by a predetermined correction coefficient, and corrects the corrected correction signal. A level matrix may be generated.

  Preferably, the group of detection positions may include a reference position, and the reference position may correspond to a column of reference elements in an N × N matrix. The signal level of the detection signal at the reference position obtained by the control unit using the polarity pattern corresponding to the third partial matrix of 1 row and N columns including the first partial matrix of the N rows and N columns of matrix, and the correction signal level matrix And an offset calculation process for calculating a difference between the element corresponding to the reference position as an offset and an element corresponding to the detection position corresponding to the intermediate submatrix in the correction signal level matrix. An offset correction process for correcting based on the offset, or an offset correction process for correcting an element other than the element corresponding to the detection position corresponding to the intermediate submatrix in the correction signal level matrix based on the offset. It's okay.

  According to this configuration, the combined detection signal when the polarity pattern corresponding to the third partial matrix in the N rows and N columns matrix represents the signal level of the detection signal at the reference position. Therefore, in the offset calculation process, it is not necessary to calculate the signal level of the detection signal using an inverse matrix, so that the process is simplified.

  Preferably, the control unit includes N matrices in a difference matrix between a matrix calculated by an operation corresponding to a product of an inverse matrix of a matrix of N rows and N columns and a composite detection signal matrix, and the correction signal level matrix. You may perform the offset calculation process which calculates the average value of an element as an offset, and the offset correction process which correct | amends each element of a correction signal level matrix based on the said offset.

  According to this configuration, N elements in the matrix of the difference between the matrix calculated by the operation corresponding to the product of the inverse matrix of the N × N matrix and the combined detection signal matrix and the reproduction signal level matrix are An offset is calculated by averaging. For this reason, an appropriate offset in which the influence of noise is reduced is calculated.

  Preferably, the correction coefficient may be a value obtained by rounding off ((N−1) / 4) to the first decimal place and multiplying by 4.

  Preferably, the control unit maximizes the total value of the elements in the row direction and the column direction from the Hadamard matrix based on the Paley method in which the number of rows and the number of columns exceeds the number of rows of the main submatrix as the main submatrix. A matrix generated by excluding rows and columns may be used.

  According to this configuration, a main submatrix is configured from a Hadamard matrix based on the Paley method.

Preferably, when the main submatrix is T rows and T columns, the main submatrix is obtained by cyclically shifting the reference matrix of 1 row and T columns by a different amount from 0 to T-1 in a certain direction. It may be a combination of T shift matrices obtained in the row direction. The integers P and Q may be selected to satisfy P> Q and that the polynomial x ^P + x ^Q +1 is an irreducible polynomial for any number x. T = 2 ^P −1. When the elements of the reference matrix are called the (T-1) th element from the 0th element in the order of arrangement, the (P-1) th element from the 0th element in the reference matrix is “1”. Or “−1”. Both “1” and “−1” may be included in the (P−1) th element from the 0 th element. When the (W−P) th element and the (W−Q) th element are the same, the Wth element is “−1”, the (W−P) th element and (W−Q) If the th element is different, the W th element may be “1”.

  According to this configuration, the main submatrix is configured from a combination of 1-row T-column shift matrices having T elements forming an M sequence.

  Preferably, the T shift matrices may be arranged in order of the amount of shift.

  Preferably, the sensor unit is a plurality of detection elements provided corresponding to a plurality of detection positions, has a signal level according to the proximity state of the object, and has a positive polarity according to the input drive signal. Alternatively, a plurality of detection elements that respectively generate detection signals that are set to be negative may be included, and a drive unit that supplies drive signals to the plurality of detection elements according to the control of the control unit. The detection unit may include a group of detection elements corresponding to the group of detection positions, and may generate a combined detection signal corresponding to the sum of the group of detection signals generated by the group of detection elements.

  Preferably, the sensor unit may include at least one detection electrode, a plurality of drive electrodes that intersect the detection electrode, and a combined detection signal generation unit. The detection element may be a capacitor formed at the intersection of the detection electrode and the drive electrode. The drive unit may supply a drive signal to each of the plurality of drive electrodes. A group of capacitors as a group of detection elements may be formed between one detection electrode and a plurality of drive electrodes. The combined detection signal generation unit generates a combined detection signal for each of the plurality of detection electrodes according to the sum of the group of detection signals that express the capacitance of the group of capacitors in either positive or negative polarity. Good.

Preferably, the number of the drive electrodes in the sensor unit may be smaller than the number of the detection electrodes.
By reducing the number of drive electrodes, the number of combined detection signals required for reproduction of each detection signal in the signal reproduction unit is reduced, and the number of generations of the combined detection signal in the combined detection signal generation unit is reduced. The time required for playback is shortened.

  A third aspect of the present invention relates to a method for controlling an input device that inputs information according to the proximity state of an object at a plurality of detection positions. The input device detects at least one proximity state of the object at the group of detection positions, and generates at least one detection unit that generates a combined detection signal corresponding to the sum of the group of detection signals obtained as a result of the detection for the group of detection positions. And a sensor unit capable of controlling the positive and negative polarities of the detection signal having a signal level corresponding to the proximity state at each detection position. The control method of the input device according to the third aspect is a group of combined detection signals composed of combined detection signals in which polar patterns, which are a group of polarities set in the group of detection signals, are different from each other. Based on controlling the sensor unit to generate a group of combined detection signals composed of the same number of combined detection signals as the signal in the detection unit, and based on the group of combined detection signals generated by the detection unit, Reproducing the signal level of the group of detection signals. A group of detection positions in one detection unit is N, and positive or negative polarity set in the detection signal is represented by “1” or “−1” and set for a detection signal that is not added to the combined detection signal. The polarity to be displayed is represented by “0”, and the polarity pattern set to a group of detection signals composed of N detection signals is one row having one of the elements “1”, “−1”, and “0”. When a group of polarity patterns consisting of N partial patterns and a group of N polar patterns is represented by an N-row N-column matrix consisting of N partial matrices, the inverse of the N-row N-column matrix is obtained. An extended inverse matrix in which one of an element greater than “0” and an element below “0” in the matrix is replaced with “1” and the other is replaced with “−1”, and one detection unit A combined detection signal matrix of N rows and 1 column having the generated group of combined detection signals as elements; The operation corresponding to the product, the reproduction signal level matrix of N rows and one column is generated. The matrix of N rows and N columns includes a first submatrix with 1 row and N columns, and a second submatrix with (N−1) rows and N columns. The first submatrix has one element that is “1” or “−1” and (N−1) elements that are “0”. In the second submatrix, the sum of the elements in any row is “0”. The second submatrix has a main submatrix that is a submatrix with (N-1) rows (N-1) columns. In the main submatrix, the sum of the elements in any row is “1” or “−1”.

  A fourth aspect of the present invention relates to a control method for an input device that inputs information according to the proximity state of an object at a plurality of detection positions. The input device detects at least one proximity state of the object at the group of detection positions, and generates at least one detection unit that generates a combined detection signal corresponding to the sum of the group of detection signals obtained as a result of the detection for the group of detection positions. And a sensor unit capable of controlling the positive and negative polarities of the detection signal having a signal level corresponding to the proximity state at each detection position. The control method of the input device according to the fourth aspect is a group of combined detection signals composed of combined detection signals in which polar patterns, which are a group of polarities set in the group of detection signals, are different from each other. Based on controlling the sensor unit to generate a group of combined detection signals composed of the same number of combined detection signals as the signal in the detection unit, and based on the group of combined detection signals generated by the detection unit, Reproducing the signal level of the group of detection signals. A group of detection positions in one detection unit is N, and positive or negative polarity set in the detection signal is represented by “1” or “−1” and set for a detection signal that is not added to the combined detection signal. The polarity to be displayed is represented by “0”, and the polarity pattern set to a group of detection signals composed of N detection signals is one row having one of the elements “1”, “−1”, and “0”. When a group of polarity patterns consisting of N partial patterns and a group of N polar patterns is represented by an N-row N-column matrix consisting of N partial matrices, the inverse of the N-row N-column matrix is obtained. An extended inverse matrix in which one of an element greater than “0” and an element below “0” in the matrix is replaced with “1” and the other is replaced with “−1”, and one detection unit A combined detection signal matrix of N rows and 1 column having the generated group of combined detection signals as elements; The operation corresponding to the product, the reproduction signal level matrix of N rows and one column is generated. The matrix of N rows and N columns includes an intermediate submatrix of M rows and M columns. The intermediate submatrix includes a first submatrix with 1 row and M columns, and a second submatrix with (M−1) rows and M columns. The first submatrix has one reference element that is “1” or “−1” and (M−1) elements that are “0”. In the second submatrix, the sum of the elements in any row is “0”. The second submatrix has a main submatrix that is a submatrix with (M−1) rows (M−1) columns. In the main submatrix, the sum of the elements in any row is “1” or “−1”. Of the N-row N-column matrix, each of the 1-row N-column sub-matrices that do not overlap the intermediate sub-matrix is “1” or “−1” and “0” (N− 1) All N-by-1 sub-matrices that have one element and do not overlap the intermediate sub-matrix are each one element that is “1” or “−1” and “0” (N− 1) It has an element.

  A fifth aspect of the present invention is a program that causes a computer to execute the control method for an input device according to the third aspect or the fourth aspect.

  According to the present invention, the original detection signal can be calculated from the sum of the detection signals at a plurality of detection positions at which the proximity state of the object is detected, the signal level of the sum of the detection signals can be suppressed, and the sum of the detection signals can be reduced. Thus, variations in the number of detection positions where the original detection signal can be calculated can be increased.

It is a block diagram of the input device which concerns on 1st Embodiment of this invention. FIG. 2 is a diagram illustrating an example of a detection signal calculated by an inverse matrix and a correction signal calculated by an extended inverse matrix when a drive matrix based on the Paley method is used in the input device illustrated in FIG. 1. FIG. 3 is a diagram illustrating an example of a detection signal calculated by an inverse matrix and a correction signal calculated by an extended inverse matrix when a drive matrix based on an M sequence is used in the input device illustrated in FIG. 1. It is a figure which shows the example of the detection signal calculated by an inverse matrix, and the correction signal calculated by an extended inverse matrix at the time of using the drive matrix based on a ternary code with the input device shown in FIG. It is a figure which shows the other example of the detection signal calculated by an inverse matrix, and the correction signal calculated by an extended inverse matrix at the time of using the drive matrix based on a ternary code with the input device shown in FIG. FIG. 2 is a diagram illustrating an example of a detection signal calculated by an inverse matrix and a correction signal calculated by an extended inverse matrix when a drive matrix based on a 1hot + ternary code is used in the input device illustrated in FIG. 1. It is a figure which shows the other example of the detection signal calculated by an inverse matrix, and the correction signal calculated by an extended inverse matrix at the time of using the drive matrix based on 1hot + ternary code with the input device shown in FIG. 2 is a flowchart for explaining the operation of a control unit shown in FIG. 2 is a flowchart for explaining the operation of a signal reproduction unit shown in FIG.

(Constitution)
Hereinafter, an input device for inputting information according to the proximity state of an object at a plurality of detection positions according to an embodiment of the present invention will be described. As shown in FIG. 1, the input device 100 of this embodiment includes a sensor unit 200, a processing unit 300, and a storage unit 330.

  The sensor unit 200 is a device that detects the proximity state of an object, and includes a plurality of detection units 260. One detection unit 260 detects the proximity state of an object at a group of detection positions 235, respectively. When a group of detection signals is obtained as a detection result, the detection unit 260 generates a combined detection signal corresponding to the sum of the group of detection signals. The group of detection signals obtained at the group of detection positions 235 has a signal level corresponding to the proximity state of the object, and has positive and negative polarities. The sensor unit 200 can control the polarity (positive or negative) of the detection signal obtained at each detection position 230 in accordance with polarity pattern information provided from the control unit 310 (to be described later) of the processing unit 300.

  In the example of FIG. 1, the sensor unit 200 includes a first drive electrode 210a to an eleventh drive electrode 210k (hereinafter also referred to as drive electrode 210 without distinction), a first detection electrode 220a, and a second detection electrode. 220b (hereinafter also referred to as detection electrode 220 without distinction). The drive electrodes 210 are all arranged substantially parallel to each other in the same layer. The detection electrodes 220 are all arranged in parallel with each other in the same layer. The drive electrode 210 and the detection electrode 220 are arranged in different layers, and when viewed from a direction orthogonal to these layers, they appear to intersect each other as shown in FIG. In this specification, when the drive electrode 210 and the detection electrode 220 cross each other, it means that the drive electrode 210 and the detection electrode 220 are not in contact with each other and are close to each other.

  The position where one drive electrode 210 and one detection electrode 220 intersect is the detection position 230 described above. At each detection position 230, a detection element 240 as a capacitor having the drive electrode 210 and the detection electrode 220 as components is formed. For the sake of brevity, FIG. 1 shows the detection position 230 and the detection element 240 only at the position where the first drive electrode 210a and the first detection electrode 220a intersect. All positions where 220 intersects become detection positions 230, and a detection element 240 is formed at each detection position 230. Each detection element 240 generates a detection signal whose signal level changes according to the distance between the detection position 230 and an operating body such as a finger.

  Specifically, this detection signal is a charge accumulated in a capacitor as the detection element 240. Since a predetermined drive voltage is applied between one drive electrode 210 and one detection electrode 220 by a drive unit 270 described later, the amount of charge accumulated in the capacitor as the detection element 240 (signal of the detection signal) Level) represents a capacitance between one drive electrode 210 and one detection electrode 220. Further, the polarity of the charge accumulated in the capacitor as the detection element 240 (the polarity of the detection signal) is controlled according to the polarity of the drive voltage applied by the drive unit 270.

  The first detection electrode 220a intersects the first drive electrode 210a to the eleventh drive electrode 210k. The second detection electrode 220b intersects the third drive electrode 210c to the ninth drive electrode 210i. The eleven detection positions 230 belonging to the first detection electrode 220a are collectively referred to as a first group of detection positions 235a. The seven detection positions 230 belonging to the second detection electrode 220b are collectively referred to as a second group of detection positions 235b. The first group of detection positions 235a and the second group of detection positions 235b respectively correspond to the group of detection positions 235 described above.

  The drive electrodes 210 and the detection electrodes 220 of the present embodiment are merely examples, and the number, shape, and arrangement of the drive electrodes 210 and the detection electrodes 220 are not limited to those shown in the present embodiment. Although two detection electrodes 220 are shown in FIG. 1, the number of detection electrodes 220 may be one or three or more. Although eleven drive electrodes 210 are shown in FIG. 1, the drive electrodes 210 may be 10 or less or 12 or more. The number of detection positions 230 belonging to one detection electrode 220 may be different from both 7 and 11. The same number of detection positions 230 may belong to at least two of the plurality of detection electrodes 220.

  The sensor unit 200 further includes a first combined detection signal generation unit 250a and a second combined detection signal generation unit 250b (hereinafter sometimes referred to as a combined detection signal generation unit 250 without distinction). The first combined detection signal generator 250a is connected to one end of the first detection electrode 220a, and generates a combined detection signal by combining the detection signals on the first detection electrode 220a. In the present embodiment, synthesis refers to adding detection signals having polarity. The second combined detection signal generation unit 250b is connected to one end of the second detection electrode 220b, and generates a combined detection signal by combining the detection signals on the second detection electrode 220b.

  For example, the combined detection signal generation unit 250 includes a charge amplifier that outputs a combined detection signal corresponding to the sum of charges (detection signals) transferred from the respective detection elements 240 through the detection electrodes 220, and a combined detection signal output from the charge amplifier. Is converted to a digital signal and output to the processing unit 300. In this case, an AD converter may be provided for each charge amplifier, or output signals from a plurality of charge amplifiers may be converted into digital signals by one AD converter.

  The plurality of detection elements 240 corresponding to the plurality of detection positions 230 belonging to the first detection electrode 220a and the first combined detection signal generation unit 250a are collectively referred to as a first detection unit 260a. The plurality of detection elements 240 corresponding to the plurality of detection positions 230 belonging to the second detection electrode 220b and the second combined detection signal generation unit 250b are collectively referred to as a second detection unit 260b. The first detector 260a and the second detector 260b correspond to the detector 260 described above. The sensor unit 200 may include three or more detection units 260. The number of detection positions 230 included in one detection unit 260 may be different from or the same as the number of detection positions 230 included in another detection unit 260. In this embodiment, one detection electrode 220 includes one combined detection signal generation unit 250. However, a plurality of detection electrodes 220 may be connected to one combination detection signal generation unit 250 and switched by a multiplexer. Good.

  The sensor unit 200 further includes a drive unit 270. The drive unit 270 applies a drive signal to each drive electrode 210 by a multi-drive method based on a polarity pattern input from a control unit 310 (to be described later) of the processing unit 300. In the multi-drive method, drive signals are simultaneously applied to the plurality of drive electrodes 210.

  The polarity pattern is composed of a plurality of elements representing polarity. One element specifies whether a detection signal corresponding to one drive electrode 210 is generated with a positive polarity or a negative polarity. In the polarity pattern, the positive polarity is represented by “1”, the negative polarity is represented by “−1”, and the designation not to generate the detection signal is represented by “0”. Each polarity pattern is created so that the number of positive polarity and the number of negative polarity included in one polarity pattern approximate.

  At the detection position 230 on the drive electrode 210 designated as “1”, the detection signal is output with positive polarity. At the detection position 230 on the drive electrode 210 designated as “−1”, the detection signal is output with a negative polarity. At the detection position 230 on the drive electrode 210 designated as “0”, no detection signal is generated and added to the combined detection signal. For example, the polarity of the detection signal is selected depending on which of the drive electrode 210 and the detection electrode 220 is set to a high potential. Other setting methods may be used as long as the polarity of the detection signal can be set.

  The processing unit 300 is a central processing unit as a computer, and implements various functions including the control unit 310 and the signal reproduction unit 320 by reading and executing programs and data stored in the storage unit 330. The processing unit 300 may be realized by a dedicated logic circuit such as ASIC (application specific integrated circuits).

  In the example of FIG. 1, the processing unit 300 includes a control unit 310 and a signal reproduction unit 320.

  The control unit 310 controls the sensor unit 200 so that each of the plurality of detection units 260 generates a group of combined detection signals. The group of combined detection signals generated by the individual detection units 260 is composed of a plurality of combined detection signals having different polarity patterns (a group of polarities set in the group of detection signals that are the basis of the combined detection signal). The number of combined detection signals constituting the group of combined detection signals is the same as the number of combined detection signals that are the basis of the combined detection signal.

  In the detection unit 260 having N detection positions 230 from which N detection signals can be obtained, the control unit 310 generates N combined detection signals based on N different polarity patterns. To control. A set of polarity patterns used to generate a group of combined detection signals in one detection unit 260 is referred to as a group of polarity patterns. A group of polarity patterns including N polarity patterns is selected for the detection unit 260 having N detection positions 230. For example, since the first detection unit 260a has eleven detection positions 230, the control unit 310 selects a group of polarity patterns composed of eleven polarity patterns. Since the second detection unit 260b has seven detection positions 230, the control unit 310 selects a group of polarity patterns composed of seven polarity patterns.

  Based on the group of combined detection signals generated by the detection unit 260, the signal reproduction unit 320 reproduces the signal level of the group of detection signals that is the source of the combined detection signal. The signal reproduction unit 320 may reproduce the signal level of the detection signal by directly using the group of polarity patterns used to generate the combined detection signal, and is derived from the process directly using the group of polarity patterns. The signal level of the detection signal may be reproduced by another process.

  The storage unit 330 is an instruction code of a program executed in the central processing unit (computer) in the processing unit 300, or variable data temporarily stored in the process of the processing unit 300 (a group generated in each detection unit 260). ), Constant data used for processing of the processing unit 300 (polarity pattern supplied to the driving unit 270, inverse matrix and extended inverse matrix used for reproduction of detection signal, correction coefficient, etc.) To do. The storage unit 330 includes, for example, a nonvolatile memory such as a ROM, a RAM, and a flash memory.

(Polarity pattern)
Next, the polarity pattern will be described in detail. Let N be the number of detection positions 230 constituting a group of detection positions 235.

  The signal levels of the N detection signals corresponding to the N detection positions 230 are expressed by a signal level matrix C of N rows and 1 column as shown in Equation 1. The subscript of the element of the signal level matrix C indicates which position each element corresponds to when the detection position 230 is identified by (1) to (N).

  N composite detection signals obtained by N times of driving are represented by a composite detection signal matrix A of N rows and 1 column as shown in Equation 2. The subscripts of the elements of the combined detection signal matrix A indicate the number of driving each element is a combined detection signal. The number of elements of the combined detection signal matrix A is equal to the number of elements of the signal level matrix C. That is, driving is performed a number of times equal to the number of detection positions 230.

  The drive matrix D of N rows and N columns shown in Equation 3 specifies whether the detection signal at each detection position 230 is generated with positive or negative polarity, and further specifies the case where the detection signal is not generated. The

  The j-th row of the drive matrix D shows the polarity pattern in the j-th drive. The drive matrix D represents one polarity pattern in which each row is used to generate one combined detection signal, and constitutes a group of polarity patterns as a whole. The column of the drive matrix D indicates to which drive electrode 210 each polarity constituting the polarity pattern is applied. Although a specific example will be described later, the element of the drive matrix D is any one of “0”, “1”, and “−1”. In each polarity pattern, the drive matrix D is created so that the number of “1” elements corresponding to positive polarity and the number of “−1” elements corresponding to negative polarity are close to each other.

  Using the drive matrix D, the relationship between the signal level matrix C and the combined detection signal matrix A is expressed as in Expression 4.

  When Expression 4 is expressed as a component, it is expressed as Expression 5.

As shown in Equation 5, when the polarity pattern of the j-th row of the drive matrix D shown in Equation 3 is used, the combined detection signal a _j is d _j1 c ₁ +... + D _jN c _N. Detection signal at the detection position (r) of the detection position 230 is the product _d jr _{c r} between the signal level _{c r} polarity _{d jr} and the detection signal. That is, each composite detection signal is represented as the sum of a group of detection signals obtained by setting either the positive or negative polarity indicated by the polarity pattern to the signal level of the detection signal at the group of detection positions 230. The

  On the drive electrode whose polarity is set to “1”, the absolute value of the detection signal is equal to the signal level of the detection signal, and the polarity is positive. On the drive electrode whose polarity is set to “−1”, the absolute value of the detection signal is equal to the signal level of the detection signal, and the polarity is negative. Since the signal level of the detection signal is zero on the drive electrode whose polarity is set to “0”, it is not added to the combined detection signal.

  Since the number of positive polarity included in one polarity pattern is close to the number of negative polarity, the polarity of the drive signal output from the drive unit 270 (the polarity of the voltage applied between the drive electrode 210 and the detection electrode 220) ) Is less biased. Therefore, radiation noise from the drive electrode 210 and the detection electrode 220 is reduced as compared with the conventional case.

  Since the number of positive polarity and the number of negative polarity included in one polarity pattern are close, the polarity deviation in the group of detection signals that are the source of the combined detection signal is reduced, so that the group of detection signals is positively detected. The signal level of the combined detection signal is lower than when only the signal is included or when only the negative detection signal is included. Accordingly, since the processing unit 300 can sufficiently secure a dynamic range for detection of the signal level of the combined detection signal, a minute detection signal obtained in each detection element 240 can be reproduced with high sensitivity.

Next, a method for calculating the signal level matrix C from the inverse matrix D ⁻¹ of the drive matrix D will be described.

As shown in Equation 6, a signal level matrix C corresponding to the capacitance at each detection position 230 is calculated by the product of the inverse matrix D ⁻¹ of the drive matrix D and the combined detection signal matrix A.

The element of the signal level matrix C calculated from the inverse matrix D ⁻¹ may be adopted as the signal level of the final detection signal. However, when the inverse matrix D ⁻¹ includes many “0”, the detection signal multiplied by “0” is not used for the calculation, and thus the noise reduction effect is reduced. Therefore, in the present embodiment, as described below, an extended inverse matrix E ⁻¹ having a small number of zero elements and a close number of positive polarity and the number of negative polarity is used.

In addition, when the inverse matrix D ⁻¹ is composed only of “0” and “one kind of number”, “0”, “one kind of number”, and “the sign of the one kind of number are exchanged” when composed of only a few ", may be used in place of the" one number "reciprocal inverse matrix D ^-1 to multiplying the matrix the inverse matrix D ^-1 of. In this case, a signal level matrix C is obtained by multiplying the calculated matrix by the “one kind of number”. For example, when the inverse matrix D ⁻¹ is composed of “0” and “1/6”, by multiplying the inverse matrix D ⁻¹ by 6, all the elements are “0” and “1”. Since it is expressed in either one, the calculation is simplified.

Next, a method for calculating the low noise signal level matrix Z corresponding to the signal level matrix C of the detection signal from the extended inverse matrix E ⁻¹ will be described.

Since the low noise signal level matrix Z is not derived from the inverse matrix D- ¹ , it does not directly reflect the signal level of the detection signal at each detection position 230 like the signal level matrix C. However, as described in the present embodiment, since the elements of the low noise signal level matrix Z represent values obtained by reducing noise from the signal level of the detection signal, the change in capacitance at each detection position 230 can be more accurately represented. Represent.

An N-by-N extended inverse matrix E ⁻¹ as shown in Equation 7 is created in advance. The extended inverse matrix E ⁻¹ is a matrix derived from the inverse matrix D ⁻¹ . When the extended inverse matrix E ⁻¹ is used, the low noise signal level matrix Z can be calculated by a calculation similar to the inverse matrix D ⁻¹ . A method of creating the extended inverse matrix E ⁻¹ will be described later.

A matrix of N rows and 1 column as in Expression 8 is set as a reproduction signal level matrix R. The reproduction signal level matrix R is calculated by the product of the extended inverse matrix E ⁻¹ and the combined detection signal matrix A. The element of the reproduction signal level matrix R is called a reproduction signal level. Of the elements of the signal level matrix C and the elements of the reproduction signal level matrix R, elements having the same subscript correspond to the same detection position 230.

  A matrix of N rows and 1 column as shown in Equation 9 is a correction signal level matrix B. The correction signal level matrix B is calculated by dividing each element of the reproduction signal level matrix R by a common correction coefficient k. The elements of the correction signal level matrix B are called correction signal levels. Of the elements of the signal level matrix C and the elements of the correction signal level matrix B, elements having the same subscript correspond to the same detection position 230.

  A matrix of N rows and 1 column as shown in Equation 10 is defined as a low noise signal level matrix Z. When an offset matrix F of N rows and 1 column is added to the correction signal level matrix B, a low noise signal level matrix Z is obtained. The elements of the low noise signal level matrix Z are called low noise signal levels. Of the elements of the signal level matrix C and the elements of the low noise signal level matrix Z, elements having the same subscript correspond to the same detection position 230. A method for calculating the offset matrix F will be described later.

  The relative relationship between the elements of the low noise signal level matrix Z is similar to the relative relationship between the elements of the signal level matrix C. However, the low noise signal level matrix Z more accurately represents the change in capacitance at each detection position 230 in that the influence of noise is less than that of the signal level matrix C. As long as the relative relationship between the values is known, the correction signal level matrix B may be used as it is without calculating the low noise signal level matrix Z.

(Determination of driving matrix, extended inverse matrix, correction coefficient and offset matrix)
Next, how to determine a driving matrix, an extended inverse matrix, a correction coefficient, and an offset matrix will be described.

(Paley law)
A drive matrix D of N rows and N columns based on the Paley method can be created when the number N of detection positions 230 constituting the group of detection positions 235 is a prime number. The driving matrix D based on the Paley method is a partial matrix of the Hadamard matrix H generated by the Paley method. The Hadamard matrix H is a square matrix whose elements are either 1 or −1 and whose rows are orthogonal to each other. Any two rows of the Hadamard matrix H represents the vertical vector each other, n following Hadamard matrix H, using the identity matrix I _n of n × n, satisfying the properties of the formula 11.

  The Paley method is a method of generating a (q + 1) -order Hadamard matrix H for an arbitrary prime number q. The Hadamard matrix H is selected so that both the number of rows and the number of columns are larger than N and closest to N. The driving matrix D based on the Paley method is a partial matrix obtained by removing from the Hadamard matrix H the row having the largest absolute value of the sum in the row and the column having the largest absolute value of the sum in the column. When the number of detection positions 230 is a prime number, the drive matrix D is created by removing one row and one column from the Hadamard matrix H generated by the Paley method.

  For example, when N = 11, a 12th-order Hadamard matrix H shown in Expression 12 is used.

  Excluding the first row where the absolute value of the sum in the row is the maximum and the first column where the absolute value of the sum in the column is the maximum, the drive matrix D shown in Equation 13 is obtained.

Equation 14 shows a matrix obtained by multiplying the inverse matrix D ⁻¹ of the drive matrix D with N = 11 by 6. The inverse matrix D ⁻¹ itself includes a fraction “1/6”, but in Equation 14, 6 is multiplied for ease of viewing.

In the inverse matrix D- ¹ , when an element greater than "0" is replaced with "1" and an element equal to or less than "0" is replaced with "-1", an extended inverse matrix E- ¹ is obtained. Expression 15 is an extended inverse matrix E ⁻¹ in the case of N = 11. When N = 11, the correction coefficient k is 6. As the correction coefficient k, for example, a reciprocal of a fraction included in the inverse matrix D ⁻¹ is selected.

The graph 400 of FIG. 2 corresponds to the exemplary N = 11 drive matrix D shown in Equation 13, and is a graph of the signal level of an exemplary detection signal calculated using the inverse matrix D ^−1. 401 and an exemplary correction signal level graph 402 calculated using the extended inverse matrix E ⁻¹ are shown. The horizontal axis corresponds to the difference in the columns of the drive matrix D and shows the difference in the detection position 230. A large mountain near the detection position (5) to the detection position (7) represents a position where the finger is in contact.

  It has been empirically known that when the graph 402 is moved in the vertical direction, a shape close to that of the graph 401 is obtained. The amount of movement corresponds to each element of the offset matrix F and is substantially constant regardless of the detection position 230. Therefore, when using the driving matrix D based on the Paley method, each element of the offset matrix F can be approximated by a substantially constant offset f. The offset f is, for example, an average of the difference between the signal level of the detection signal and the correction signal level at each position as shown in Expression 16. This operation corresponds to an operation for obtaining an average of N elements in a difference matrix between the signal level matrix C calculated by Expression 6 and the correction signal level matrix B. Each element of the offset matrix F may be changed for each detection position 230, or may be determined by other methods. The offset signal f may be all 0, and the correction signal level matrix B may be used for detecting the operating body.

(M series)
The driving matrix D of N rows and N columns based on the M series is a combination of N matrices obtained by cyclically shifting a matrix serving as a reference of 1 row and N columns by different amounts in the row direction. The matrix element used as a reference is a numerical sequence called an M series.

In order to determine the M-sequence, first, an integer P and an integer Q that satisfy the following first condition and second condition are selected. The first condition is that P> Q. The second condition is that the polynomial x ^P + x ^Q +1 is an irreducible polynomial for an arbitrary number x. An irreducible polynomial is a polynomial that cannot be factored any further.

The M-sequence sequence is composed of either “0” or “1”. Of the sequence of the M series, the W th value expressed as x _W. W increases from 0 by 1. _{x P-1} from x ₀ is arbitrarily defined as the initial value. The initial value includes both “0” and “1”. As shown in a linear recurrence formula of formula 17, _{x W is} determined by the exclusive OR of the _{x W-P} and _{x W-Q.}

The sequence of M series circulates in units of (2 ^P −1). As a reference matrix, only (2 ^P −1) number sequences for one cycle are used. Therefore, it is necessary to satisfy N = 2 ^P −1 in relation to the number N of detection positions 230 constituting the group of detection positions 235.

In a 1-row N-column matrix obtained by arranging x ₀ to x _N-1 in order from left to right, “0” is converted to “−1” and “1” is maintained as a reference matrix. is there. When N shift matrices obtained by cyclically shifting the reference matrix by different amounts from 0 to N−1 are connected in the row direction, a drive matrix D of N rows and N columns is obtained. When cyclically shifting by one in the right direction, the rightmost element is added to the left and the whole is shifted by one to the right. When cyclically shifting by one in the left direction, the leftmost element is added to the right and the whole is shifted by one to the left.

  All rows of one drive matrix D are a set of shift matrices obtained by cyclically shifting the reference matrix by a different amount in the left direction, or by cyclically shifting the reference matrix by a different amount in the right direction. This is the set of shift matrices obtained. In one drive matrix D, it is preferable that the shift matrices are arranged in order of the amount of shift.

When the created drive matrix D is viewed, it can be explained as follows. The driving matrix D has N rows and N columns. The driving matrix D is a combination of N shift matrices obtained by cyclically shifting a matrix serving as a reference of 1 row and N columns by different amounts from 0 to N−1 in the row direction. The integers P and Q are selected to satisfy P> Q and that the polynomial x ^P + x ^Q +1 is an irreducible polynomial for any number x. N = 2 ^P −1. When the elements of the reference matrix are referred to as the (N-1) th element from the 0th element in order, the (P-1) th element from the 0th element in the reference matrix is “1”. "-1", the (P-1) th element from the 0th element includes both "1" and "-1", and the (WP) th element When the (WQ) -th element is the same, the W-th element is “−1”, and when the (WP) -th element and the (W-Q) -th element are different. , The Wth element is “1”.

In the inverse matrix D ⁻¹ of the drive matrix D, when an element greater than “0” is replaced with “1” and an element equal to or less than “0” is replaced with “−1”, an extended inverse matrix E ⁻¹ is obtained. The offset matrix F is calculated in the same manner as the driving matrix D based on the Paley method.

  Equation 18 is an exemplary drive matrix D for N = 15. The top one-row N-column submatrix is a reference matrix, and is also a shift matrix with a shift amount of zero. Each row is a shift matrix obtained by shifting the matrix above one by one in the left direction.

Equation 19 is an exemplary extended inverse matrix E ⁻¹ corresponding to Equation 18. In the case of Equation 19, the correction coefficient k is 16. As the correction coefficient k, for example, a reciprocal of a fraction included in the inverse matrix D ⁻¹ is selected.

The graph 410 of FIG. 3 corresponds to the exemplary N = 15 drive matrix D shown in Equation 18, and is a graph of the signal level of an exemplary detection signal calculated using the inverse matrix D ^−1. 411 and a graph 412 of an exemplary correction signal level calculated using the extended inverse matrix E- ¹ . The horizontal axis corresponds to the difference in the columns of the drive matrix D and shows the difference in the detection position 230. A large mountain near the detection position (5) to the detection position (7) represents a position where the finger is in contact.

  It is empirically known that when the graph 412 is moved in the vertical direction, the shape becomes close to the graph 411. The amount of movement corresponds to each element of the offset matrix F and is substantially constant regardless of the detection position 230. Therefore, when the driving matrix D based on the M series is used, each element of the offset matrix F can be approximated by a substantially constant offset f. The offset f is an average of the difference between the signal level of the detection signal and the correction signal level at each position as shown in Expression 16. Each element of the offset matrix F may be changed for each detection position 230, or may be determined by other methods. The offset signal f may be all 0, and the correction signal level matrix B may be used for detecting the operating body.

(Ternary code)
The driving matrix D of N rows and N columns based on the ternary code includes a first partial matrix of 1 row and N columns and a second partial matrix of (N-1) rows and N columns. The first submatrix has one element that is “1” or “−1” and (N−1) elements that are “0”. In the second submatrix, the sum of the elements in any row is “0”. The second submatrix has a main submatrix that is a submatrix with (N-1) rows (N-1) columns. In the main submatrix, the sum of the elements in any row is “1” or “−1”. The main submatrix is, for example, the same as the driving matrix D based on the Paley method and the driving matrix D based on the M series.

  In other words, first, either the driving matrix D based on the Paley method or the driving matrix D based on the M series is set as a main submatrix. Next, a (N−1) × 1 submatrix is added to the left of the main submatrix to create a (N−1) × N second submatrix. Next, in the second submatrix, elements other than the main submatrix are set so that the sum of the elements in any row is “0”. Next, a first partial matrix of 1 row and N columns is added on the second partial matrix. In the first submatrix, one element is set to “1” or “−1”, and the other (N−1) elements are set to “0”.

  In the first submatrix, the element set to “1” or “−1” is preferably the end element. In the first submatrix, the column of elements set to “1” or “−1” is preferably the same as the column that does not overlap the main submatrix in the second submatrix.

In the inverse matrix D ⁻¹ of the drive matrix D, when an element greater than “0” is replaced with “1” and an element equal to or less than “0” is replaced with “−1”, an extended inverse matrix E ⁻¹ is obtained. With this setting, when the reproduction signal level matrix R is calculated, the product of the extended inverse matrix E ⁻¹ and the combined detection signal matrix A can be obtained by the sum and difference of the elements of the combined detection signal matrix A. The calculation is simplified compared to the case where other numbers are included.

  The correction coefficient k is calculated by 4 × round ((N−1) / 4). round ((N-1) / 4) means that ((N-1) / 4) is rounded off to the first decimal place.

  Equation 20 is an example of an exemplary drive matrix D for N = 16. In the example of Expression 20, the 15 × 15 submatrix at the lower right is the main submatrix, and is equal to the driving matrix based on the M sequence when N = 15.

  In the example of Expression 20, the number of positive polarity “1” in the polarity pattern of the first row is 0, the number of negative polarity “−1” is 1, and none of them is “0”, The sum is “−1”. The number of positive polarity “1” s in the polar patterns in the second and subsequent rows is 8, the number of negative polarity “−1” is 8, and none of them is “0”, and the sum of the elements is “0”. It is. That is, the number of positive polarity and the number of negative polarity included in the polar pattern are close.

Equation 21 is the extended inverse matrix E ⁻¹ of Equation 20.

  Equation 22 is an exemplary drive matrix D for N = 20. In the example of Equation 22, the 19 × 19 submatrix at the lower right is the main submatrix, which is equal to the driving matrix based on the Paley method when N = 19.

  In the example of Formula 22, in the polarity pattern in the first row, the number of positive polarity “1” is 0, the number of negative polarity “−1” is 1, and none of them is “0”, which is 19 elements. Is the sum of “−1”. In the polar patterns in the second and subsequent rows, the number of positive polarity “1” is 10, the number of negative polarity “−1” is 10, and none of them is “0”, and the sum of elements is “0”. It is. That is, the number of positive polarity and the number of negative polarity included in the polar pattern are close.

Equation 23 is the extended inverse matrix E ⁻¹ of Equation 22.

The graph 420 of FIG. 4 corresponds to the exemplary N = 16 drive matrix D shown in Equation 20, and is a graph of the signal level of the exemplary detection signal calculated using the inverse matrix D ^−1. 421 and an exemplary correction signal level graph 422 calculated using the extended inverse matrix E- ¹ .

The graph 430 of FIG. 5 corresponds to the exemplary N = 20 drive matrix D shown in Equation 22, and is a graph of the signal level of the exemplary detection signal calculated using the inverse matrix D ^−1. 431 and an exemplary correction signal level graph 432 calculated using the extended inverse matrix E ⁻¹ .

  In the graph 420 in FIG. 4 and the graph 430 in FIG. 5, the horizontal axis corresponds to the difference in the columns of the drive matrix D and indicates the difference in the detection position 230. A large mountain near the detection position (5) to the detection position (7) in FIG. 4 and a large mountain near the detection position (5) to the detection position (7) and the detection position (18) to the detection position (19) in FIG. The mountain represents the position where the finger is in contact.

  It has been empirically known that when the graph 422 in FIG. 4 is moved in the vertical direction, a shape close to the graph 421 is obtained, and when the graph 432 in FIG. 5 is moved in the vertical direction, a shape close to the graph 431 is obtained. The amount of movement corresponds to each element of the offset matrix F and is substantially constant regardless of the detection position 230. Therefore, when the driving matrix D based on the ternary code is used, each element of the offset matrix F can be approximated by a substantially constant offset f. The offset f is an average of the difference between the signal level of the detection signal and the correction signal level at each position as shown in Expression 16. Each element of the offset matrix F may be changed for each detection position 230, or may be determined by other methods. The offset signal f may be all 0, and the correction signal level matrix B may be used for detecting the operating body.

  The value of N that can create the driving matrix D based on the Paley method and the driving matrix D based on the M series is limited. However, if the drive matrix D based on the Paley method and the drive matrix D based on the M sequence can be created in the number (N−1), the drive matrix D based on the ternary code can be created in N. That is, by adopting the drive matrix D based on the ternary code, N variations that can create the drive matrix D are expanded.

(1 hot + ternary code)
A drive matrix D of N rows and N columns based on a 1hot + ternary code includes an intermediate submatrix of M rows and M columns. The intermediate submatrix is a driving matrix based on the ternary code described above. Of the driving matrix D, each of the 1-row N-column sub-matrices that do not overlap the intermediate sub-matrix each has one element that is “1” or “−1” and (N−1) that is “0”. With the elements of In the driving matrix D, all the N-row and 1-column sub-matrices that do not overlap the intermediate sub-matrix each have one element that is “1” or “−1” and (N−1) that are “0”. With the elements of The difference between N and M is not limited to 1, and may be 2 or more.

  The drive matrix D has an intermediate submatrix equal to the drive matrix based on the ternary code. As described above, since the driving matrix based on the ternary code includes the first submatrix, the intermediate submatrix of the driving matrix D based on the 1hot + ternary code also includes the first submatrix. In the driving matrix D based on the 1hot + ternary code, the 1 × N partial matrix including the first partial matrix is referred to as a third partial matrix. As described above, the first submatrix has one element that is “1” or “−1” and (M−1) elements that are “0”. Of the third submatrix, elements that are not the first submatrix are “0”. Accordingly, the third submatrix includes one element that is “1” or “−1” and (N−1) elements that are “0”.

  A detection position 230 corresponding to one element of “1” or “−1” in the third submatrix is referred to as a reference position. When the third submatrix is applied as a polarity pattern, only the detection signal at the reference position is added to the combined detection signal. That is, if the polarity is removed from the combined detection signal, the signal level of the reference position detection signal can be directly acquired. Further, the reference position detection signal is also added to the combined detection signal when a polarity pattern corresponding to a matrix including the intermediate submatrix is applied. This property is used in calculation of an offset value described later.

  A 1 × N submatrix that does not overlap the intermediate submatrix is called a 1hot submatrix. One detection position 230 corresponding to the element “1” or “−1” of the 1hot submatrix is referred to as a 1hot detection position. When each 1-hot submatrix is applied as a polarity pattern, only the detection signal at the 1-hot detection position is added to the combined detection signal. When the polarity pattern corresponding to the matrix including the intermediate submatrix is applied, the detection signal at the 1hot detection position becomes zero and is not added to the combined detection signal.

In one embodiment of the invention, all 1hot sub-matrices are on the same side with respect to the main sub-matrix. In another embodiment of the present invention, some 1-hot sub-matrices and other 1-hot sub-matrices may be located on different sides with respect to the main sub-matrix.
In one embodiment of the present invention, elements other than the intermediate submatrix in the driving matrix D that are not “0” (“1” or “−1”) are all elements arranged on one diagonal line, That is, it is a diagonal element.
Furthermore, in one embodiment of the present invention, all elements other than the intermediate submatrix in the driving matrix D that are not “0” are “1” or all are “−1”.

In the inverse matrix D ⁻¹ of the drive matrix D, when an element greater than “0” is replaced with “1” and an element equal to or less than “0” is replaced with “−1”, an extended inverse matrix E ⁻¹ is obtained. With this setting, when the reproduction signal level matrix R is calculated, the product of the extended inverse matrix E ⁻¹ and the combined detection signal matrix A can be obtained by the sum and difference of the elements of the combined detection signal matrix A. The calculation is simplified compared to the case where other numbers are included.

  The correction coefficient k is calculated by 4 × round ((N−1) / 4). round ((N-1) / 4) means that ((N-1) / 4) is rounded off to the first decimal place.

  Note that when the driving matrix D based on the 1hot + ternary code is used, the method of dividing the correction coefficient k is different from the case of using the driving matrix D such as the ternary code described so far. That is, the division of the correction coefficient k is limited to M elements corresponding to the intermediate partial matrix of M rows and M columns among the N elements included in the reproduction signal level matrix R.

  Equation 24 is an example of an exemplary drive matrix D for N = 17. In the example of Expression 24, the lower right 16 × 16 submatrix is the intermediate submatrix. The intermediate submatrix is equal to a driving matrix based on a ternary code. Of the intermediate submatrix, the lower right 15 × 15 submatrix is the main submatrix of the driving matrix based on the ternary code. The main submatrix is equal to the driving matrix based on M-sequence when N = 15. Called detection position (1) to detection position (17) in order from the leftmost column of drive matrix D to the right. The top row corresponds to a 1hot submatrix. The second row from the top corresponds to the third submatrix. Therefore, the detection position (2) becomes the reference position.

  In the example of Expression 24, the number of positive polarity “1” is 1 in the polarity pattern of the first row and the second row, the number of negative polarity “−1” is 0, and the number of “0” which is neither is 16 Yes, the sum of the elements is “1”. In the polar patterns in the third and subsequent rows, the number of positive polarity “1” is 8, the number of negative polarity “−1” is 8, and none of them is “0”, and the sum of elements is “0”. It is. That is, the number of positive polarity and the number of negative polarity included in the polar pattern are close.

Equation 25 is the extended inverse matrix E ⁻¹ of Equation 24.

  Equation 26 is an example of an exemplary drive matrix D when N = 21. In the example of Expression 26, the lower right 20 × 20 submatrix is an intermediate submatrix. The intermediate submatrix is equal to a driving matrix based on a ternary code. Of the intermediate sub-matrix, the lower right 19-by-19 sub-matrix is the main sub-matrix of the driving matrix based on the ternary code. The main submatrix is equal to the driving matrix based on the Paley method for N = 19. Called detection position (1) to detection position (21) in order from the leftmost column of drive matrix D to the right. The top row corresponds to a 1hot submatrix. The second row from the top corresponds to the third submatrix. Therefore, the detection position (2) becomes the reference position.

  In the example of Expression 26, in the polarity patterns in the first and second rows, the number of positive polarity “1” is 1, the number of negative polarity “−1” is 0, and none of the “0” is 20 And the sum of the elements is “1”. In the polar patterns in the third and subsequent rows, the number of positive polarity “1” is 10, the number of negative polarity “−1” is 10, and none of them is “0”, and the sum of elements is “0”. It is. That is, the number of positive polarity and the number of negative polarity included in the polar pattern are close.

Equation 27 is the extended inverse matrix E ⁻¹ of Equation 26.

The graph 440 of FIG. 6 corresponds to the exemplary drive matrix D of Equation 24 for N = 17, and is a graph of the signal level of an exemplary detection signal calculated using the inverse matrix D ^−1. 441, an exemplary corrected signal level graph 442 calculated using the extended inverse matrix E- ^1, and a difference graph 443 of the graph 442 minus the graph 441.

The graph 450 of FIG. 7 corresponds to the exemplary drive matrix D of Equation 26 when N = 21, and is a graph of the signal level of the exemplary detection signal calculated using the inverse matrix D ^−1. 451, an exemplary correction signal level graph 452 calculated using the extended inverse matrix E- ^1, and a graph 453 of the difference of the graph 452 minus the graph 451.

  In the graph 440 in FIG. 6 and the graph 450 in FIG. 7, the horizontal axis corresponds to the difference in the columns of the drive matrix D and indicates the detection position 230. A large mountain near the detection position (5) to the detection position (7) in FIG. 6 and a large mountain near the detection position (5) to the detection position (7) and the detection position (18) to the detection position (20) in FIG. The mountain represents the position where the finger is in contact.

As shown in the difference graph 443 in FIG. 6 and the difference graph 453 in FIG. 7, the signal level of the detection signal calculated using the inverse matrix D ⁻¹ and the calculation using the extended inverse matrix E ^−1. The difference from the corrected signal level is substantially zero at the detection position (1), but has a certain constant magnitude at other detection positions.

  The detection position (1) in FIG. 6 and the detection position (1) in FIG. 7 correspond to the 1hot detection position. The detection signal at the detection position (1) is added to the combined detection signal only when the polarity pattern corresponding to the 1hot submatrix is applied, and is not added to the combined detection signal when another polarity pattern is applied.

  When a portion corresponding to the detection position other than the detection position (1) in the graph 442 in FIG. 6 is moved upward by a common offset value, a shape close to the graph 441 is obtained. In FIG. 7, when a portion corresponding to a detection position other than the detection position (1) in the graph 452 is moved upward by a common offset value, a shape close to the graph 451 is obtained.

This movement is realized by setting an element corresponding to the detection position (1) among the elements of the offset matrix F to 0 and setting elements corresponding to other detection positions to a common offset value. The difference between the signal level of the detection signal calculated using the inverse matrix D ⁻¹ and the correction signal level calculated using the extended inverse matrix E ⁻¹ at the detection position (2) is simply calculated. Therefore, it is preferable to use the difference at the detection position (2) as a common offset value.

The detection position (2) is a reference position. As described above, when the polarity pattern corresponding to the third partial matrix of the drive matrix D is applied, a detection signal at the reference position is obtained as a combined detection signal. The signal level of the detection signal at this reference position is referred to as a first value. The first value is used as the signal level of the detection signal at the detection position (2) calculated using the inverse matrix D- ¹ . On the other hand, the correction signal level at the detection position (2) calculated using the extended inverse matrix E ⁻¹ is set as the second value. A value obtained by subtracting the second value from the first value is set as an offset value.

In the case of FIG. 6, the offset value is added to the correction signal levels of the detection position (2) to the detection position (17) other than the detection position (1) which is the 1-hot detection position. In the case of FIG. 7, the offset value is added to the correction signal levels of the detection position (2) to the detection position (17) other than the detection position (1) that is the 1-hot detection position. According to this method, when the signal level of the detection signal at the reference position is acquired, it is not necessary to calculate using the inverse matrix D ⁻¹ , so that the process is simple. In another embodiment of the present invention, the offset value may be subtracted from the correction signal level at the detection position (1) that is the 1-hot detection position. This method can also eliminate the relative offset value difference between the correction signal level at the detection position (1) and the correction signal level at the detection position (2) to the detection position (17).

  The value of N that can create the driving matrix D based on the Paley method and the driving matrix D based on the M series is limited. However, if the drive matrix D based on the Paley method and the drive matrix D based on the M sequence can be created in the number (N−1), the drive matrix D based on the ternary code can be created in N. Furthermore, the drive matrix D based on the 1hot + ternary code can create a drive matrix D for an arbitrary number N based on the drive matrix based on the ternary code. That is, N variations in which the drive matrix D can be created are expanded.

(Driving method)
Next, with reference to the flow 500 of FIG. 8, the composite detection signal generation process under the control of the control unit 310 will be described. The control unit 310 executes the program stored in the storage unit 330 to execute the composite detection signal generation process of the present embodiment while controlling the sensor unit 200.

  First, in step 501, the control unit 310 controls the sensor unit 200 to generate a group of combined detection signals corresponding to one or more groups of detection positions 235 having the same number of detection positions 230.

  First, the control unit 310 causes the first detection unit 260a of FIG. 1 to generate a group of combined detection signals. Since the number N of detection positions 230 belonging to the first detection unit 260a is 11, the polarity pattern is determined based on the drive matrix D when N = 11. N may be any other number.

  As long as the above-described constraints are satisfied, the driving matrix D may be based on any of the Paley method, M series, ternary code, and 1hot + ternary code. The number N that can create the drive matrix D based on the Paley method and the drive matrix D based on the M series is limited. However, if the drive matrix D based on the Paley method and the drive matrix D based on the M sequence can be created in the number (N−1), the drive matrix D based on the ternary code can be created in the number N. Furthermore, the drive matrix D based on the 1hot + ternary code can create a drive matrix D for an arbitrary number N based on the drive matrix based on the ternary code.

  The controller 310 sequentially transmits from the polarity pattern indicated by the first row of the drive matrix D to the polarity pattern indicated by the Nth row to the drive unit 270. The columns of the drive matrix D correspond to the first drive electrode 210a to the eleventh drive electrode 210k in FIG. The driving unit 270 performs driving once for each polarity pattern, and performs driving a total of N times. The signal reproducing unit 320 stores the combined detection signal for one time in the storage unit 330 for each driving, and stores the total N combined detection signals in the storage unit 330.

  Next, when it is determined in step 502 that a group of detection positions for which a group of combined detection signals has not been generated remains, the control unit 310 returns to step 501 to determine which of the remaining group of detection positions. For this, a group of combined detection signals are generated. When the control unit 310 determines in step 502 that there is no group of detection positions that have not generated the group of combined detection signals, the control unit 310 ends the processing.

  The control unit 310 causes the first detection unit 260a to generate a group of combined detection signals, and then causes the second detection unit 260b to generate a group of combined detection signals. Since the number N of detection positions 230 belonging to the second detection unit 260b is 7, the polarity pattern is determined based on the drive matrix D when N = 7. N may be any other number. As long as the above-described constraints are satisfied, the drive matrix D may be a drive matrix D based on any of the Paley method, M-sequence, ternary code, and 1hot + ternary code.

  The controller 310 sequentially transmits from the polarity pattern indicated by the first row of the drive matrix D to the polarity pattern indicated by the Nth row to the drive unit 270. The columns of the drive matrix D correspond to the third drive electrode 210c to the ninth drive electrode 210i in FIG. The driving unit 270 performs driving once for each polarity pattern, and performs driving a total of N times. The control unit 310 stores one combined detection signal in the storage unit 330 for each driving, and stores a total of N combined detection signals in the storage unit 330.

  Although the number of detection units 260 is two in FIG. 1, the number of detection units 260 may be one or three or more. The plurality of detection units 260 may have the same number of detection positions 230. The number of detection positions 230 belonging to one detection unit 260 may be other than the number shown in the present embodiment. A group of combined detection signals may be generated simultaneously at a plurality of groups of detection positions 235 having the same number of detection positions 230, or a group of combined detection signals may be generated separately.

  Next, the signal reproduction processing of the signal reproduction unit 320 will be described with reference to the flow 600 of FIG. The processing unit 300 executes the signal stored in the storage unit 330 to execute the signal reproduction process of the present embodiment.

  The signal reproduction process is performed for each group of detection positions 235. The signal level of the detection signal at each detection position 230 included in one group of detection positions 235 is calculated by the signal reproduction process. In the input device 100 shown in FIG. 1, based on the group of combined detection signals output from the first combined detection signal generation unit 250a, the signal of the detection signal at each detection position 230 included in the first group of detection positions 235a. The level is calculated, and then, based on the group of combined detection signals output from the second combined detection signal generation unit 250b, the signal level of the detection signal at each detection position 230 included in the second group of detection positions 235b Is calculated. Note that the signal reproduction processing may be applied in any order to a plurality of groups of combined detection signals.

  First, in step 601, the signal reproduction unit 320 acquires a group of combined detection signals generated by the control of the control unit 310 from the storage unit 330.

Next, in step 602, the signal reproduction unit 320 performs a first signal reproduction process. In the first signal reproduction process, as shown in Expression 6, a signal level matrix is obtained by multiplying the inverse matrix D ⁻¹ of the drive matrix D by the synthesized detection signal matrix A composed of the stored group of synthesized detection signals. C is calculated. In addition, in order to perform calculation easily, the both sides of Formula 6 may be multiplied several times, and the fraction contained in the inverse matrix D- ¹ may be converted to 1. Each element of the signal level matrix C theoretically directly represents the signal level of the detection signal at each detection position 230, but contains a lot of noise as described above. If the signal level matrix C is not used in the subsequent offset calculation process, it is not necessary to obtain the signal level matrix C in step 602.

Next, the signal reproduction unit 320 performs a second signal reproduction process in Step 603. In the second signal reproduction process, first, as shown in Expression 8, a reproduction signal level matrix R is calculated by the product of the extended inverse matrix E ⁻¹ stored in the storage unit 330 and the combined detection signal matrix A. . Next, the signal reproduction unit 320 calculates a correction signal level matrix B by dividing the reproduction signal level matrix R by the correction coefficient k stored in the storage unit 330 as shown in Equation 9.

  Next, the signal reproduction unit 320 performs an offset calculation process in step 604.

  When the driving matrix D is based on any one of the Paley method, the M-sequence, and the ternary code, the signal reproduction unit 320 includes the signal level matrix C reproduced in the first signal reproduction process and the second signal reproduction process. The offset f representing the average of the differences of the corresponding elements from the correction signal level matrix B reproduced in step S is calculated.

  When the driving matrix D is based on a 1hot + ternary code, the signal reproduction unit 320 first determines the reference position from the combined detection signal when the polarity pattern corresponding to the third partial matrix of the driving matrix D is applied. The signal level of the detection signal is acquired as the first value. Next, the signal reproduction unit 320 sets the correction signal level at the reference position as the second value in the correction signal level matrix B reproduced in the second signal reproduction process, and offsets the value obtained by subtracting the second value from the first value. Calculate as a value.

  Next, in step 605, the signal reproduction unit 320 performs an offset correction process.

  When the drive matrix D is based on any one of the Paley method, the M series, and the ternary code, the signal reproduction unit 320 performs an offset correction process as follows. That is, the signal reproduction unit 320 calculates the low noise signal level matrix Z by adding the offset f calculated in the offset calculation process to all elements of the correction signal level matrix B reproduced in the second signal reproduction process. To do.

  When the drive matrix D is based on a 1hot + ternary code, the signal reproduction unit 320 performs an offset correction process as follows. That is, the signal reproduction unit 320 adds the offset value calculated by the offset calculation process to elements other than the element corresponding to the 1hot detection position among the elements of the correction signal level matrix B.

  According to the present embodiment, by using a driving matrix based on a ternary code or a driving matrix based on a 1hot + ternary code, a change in capacitance can be detected while suppressing the influence of noise. By using the extended inverse matrix instead of the inverse matrix, the reproduction signal level can be acquired by a simple process called the sum of the combined detection signals.

  According to the present embodiment, when a driving matrix based on a 1hot + ternary code is used, the combined detection signal when the polarity pattern corresponding to the third partial matrix of the driving matrix is applied is the signal of the detection signal at the reference position. Represents a level. Therefore, in the offset calculation process, it is not necessary to calculate the signal level of the detection signal using an inverse matrix, so that the process is simplified.

  According to this embodiment, since the number of positive polarity and the number of negative polarity included in each polarity pattern are selected to be approximate, the number of positive polarity detection signals and the negative polarity that are the basis of the combined detection signal The difference from the number of detected signals is small. For this reason, the signal level of the combined detection signal of the present embodiment is smaller than when the difference between the number of positive detection signals and the number of negative detection signals that are the basis of the combined detection signal is large. Since the signal level of the combined detection signal is small, the processing unit 300 that receives the combined detection signal can sufficiently secure the dynamic range of the combined detection signal. Therefore, a minute detection signal obtained in each detection element 240 can be reproduced with high sensitivity.

  Since the difference between the number of positive detection signals and the number of negative detection signals that are the basis of the combined detection signal is small, the polarity deviation of the drive signal output from the drive unit 270 is small. As a result, radiation noise from the drive electrode 210 and the detection electrode 220 can be reduced.

  The driving matrix based on the ternary code and the driving matrix based on the 1hot + ternary code has a sum of polarities of the polarity patterns of 0 compared to the binary driving matrix based on the Paley method and the binary driving matrix based on the M-sequence. There are many parts. Therefore, compared to the case where the drive matrix based on the Paley method and the drive matrix based on the M series are used, the influence of the radiation noise can be suppressed and the change in the capacitance can be detected more accurately.

  In the driving matrix based on the ternary code and the driving matrix based on the 1hot + ternary code according to the present embodiment, the variation in the number of detection positions 230 included in the group of detection positions 235 is a binary driving matrix or M series based on the Paley method. The number of detection positions 230 that are abundant as compared to the binary drive matrix based on and that cannot be handled by the binary drive matrix can be covered. Therefore, in various input devices having different numbers and distributions of detection positions 230, it is possible to detect the proximity state of an object with high sensitivity while suppressing the influence of noise.

  The present invention is not limited to the embodiment described above. That is, those skilled in the art may make various modifications, combinations, subcombinations, and alternatives regarding the components of the above-described embodiments within the technical scope of the present invention or an equivalent scope thereof.

  For example, in the above-described embodiment, an example is given in which the number of drive electrodes 210 in the sensor unit 200 is greater than the number of detection electrodes 220. However, in other embodiments of the present invention, the number of drive electrodes is smaller than the number of detection electrodes. May be. By reducing the number of drive electrodes, the number of combined detection signals required for reproduction of each detection signal in the signal reproduction unit is reduced, and the number of generations of the combined detection signal in the combined detection signal generation unit is reduced. The time required for the reproduction can be shortened.

  For example, in the above-described embodiment, a capacitive sensor unit that synthesizes charges of a group of detection elements 240 (capacitors) whose capacitance changes according to the proximity state of an object and outputs the combined detection signal is used. However, the present invention is not limited to this example. In other words, the present invention can be applied to an input device including various types of detection elements whose physical quantities change according to the proximity state of an object.

  The present invention can be applied to various input devices. For example, the present invention can be applied to an input device in which the detection area where the detection position is arranged is not rectangular.

DESCRIPTION OF SYMBOLS 100 ... Input device, 200 ... Sensor part, 210a-k ... 1st-11th drive electrode, 220a-b ... 1st-2nd detection electrode, 230 ... Detection position, 235a-b ... 1st-2nd group Detection position, 240 ... detection element, 250a-b ... first to second combined detection signal generation unit, 260a-b ... first to second detection unit, 300 ... processing unit, 310 ... control unit, 320 ... signal reproduction Part, 330 ... storage part

Claims (20)

An input device for inputting information according to the proximity state of an object at a plurality of detection positions,
It has at least one detection unit that detects proximity states of objects at the group of detection positions and generates a combined detection signal corresponding to the sum of the group of detection signals obtained as a result of the detection at the group of detection positions. A sensor unit capable of controlling positive and negative polarities of the detection signal having a signal level corresponding to the proximity state at each detection position;
A group of the combined detection signals composed of the combined detection signals in which the polarity patterns that are the polarities of the group set in the group of detection signals are different from each other, the same number of the combined detection signals as the group of detection signals A control unit that controls the sensor unit to generate a group of the combined detection signals in the detection unit;
Based on the group of combined detection signals generated by the detection unit, a signal reproduction unit that reproduces the signal level of the group of detection signals that is the source of the combined detection signal;
The group of detection positions in one detection unit is N,
The positive or negative polarity set in the detection signal is represented by “1” or “−1”,
The polarity set for the detection signal that is not added to the combined detection signal is represented by “0”,
The polarity pattern set in the group of detection signals including the N detection signals is represented by a 1 × N submatrix having one of the elements “1”, “−1”, and “0”. ,And,
When the group of polarity patterns composed of N number of the polarity patterns is represented by a matrix of N rows and N columns composed of N number of the partial matrices,
The signal reproduction unit is an extended inverse matrix in which one of an element greater than “0” and an element less than or equal to “0” in the inverse matrix for the matrix of N rows and N columns is replaced with “1”, and the other is replaced with “− N rows by an operation corresponding to the product of the extended inverse matrix replaced by “1” and the N × 1 combined detection signal matrix having the group of combined detection signals generated by the one detection unit as elements. Generate a one-column playback signal level matrix,
The N-by-N matrix is
A first sub-matrix with 1 row and N columns;
(N-1) a second submatrix with rows and N columns,
The first submatrix is
One element that is “1” or “−1”;
(N-1) elements that are “0”,
In the second submatrix, the sum of the elements in any row is “0”;
The second submatrix has a main submatrix that is a submatrix with (N-1) rows (N-1) columns;
In the main submatrix, the sum of the elements in any row is “1” or “−1”.
Input device. The controller divides the reproduction signal level matrix by a predetermined correction coefficient to generate a corrected correction signal level matrix;
The input device according to claim 1. An input device for inputting information according to the proximity state of an object at a plurality of detection positions,
It has at least one detection unit that detects proximity states of objects at the group of detection positions and generates a combined detection signal corresponding to the sum of the group of detection signals obtained as a result of the detection at the group of detection positions. A sensor unit capable of controlling positive and negative polarities of the detection signal having a signal level corresponding to the proximity state at each detection position;
A group of the combined detection signals composed of the combined detection signals in which the polarity patterns that are the polarities of the group set in the group of detection signals are different from each other, the same number of the combined detection signals as the group of detection signals A control unit that controls the sensor unit to generate a group of the combined detection signals in the detection unit;
Based on the group of combined detection signals generated by the detection unit, a signal reproduction unit that reproduces the signal level of the group of detection signals that is the source of the combined detection signal;
The group of detection positions in one detection unit is N,
The positive or negative polarity set in the detection signal is represented by “1” or “−1”,
The polarity set for the detection signal that is not added to the combined detection signal is represented by “0”,
The polarity pattern set in the group of detection signals including the N detection signals is represented by a 1 × N submatrix having one of the elements “1”, “−1”, and “0”. ,And,
When the group of polarity patterns composed of N number of the polarity patterns is represented by a matrix of N rows and N columns composed of N number of the partial matrices,
The signal reproduction unit is an extended inverse matrix in which one of an element greater than “0” and an element less than or equal to “0” in the inverse matrix for the matrix of N rows and N columns is replaced with “1”, and the other is replaced with “− N rows by an operation corresponding to the product of the extended inverse matrix replaced by “1” and the N × 1 combined detection signal matrix having the group of combined detection signals generated by the one detection unit as elements. Generate a one-column playback signal level matrix,
The matrix of N rows and N columns includes an intermediate submatrix of M rows and M columns;
The intermediate submatrix is
A first submatrix with 1 row and M columns;
(M-1) a second submatrix with rows and M columns,
The first submatrix is
One reference element that is “1” or “−1”;
(M-1) elements that are “0”,
In the second submatrix, the sum of the elements in any row is “0”;
The second submatrix has a main submatrix that is a submatrix of (M-1) rows (M-1) columns;
In the main submatrix, the sum of the elements in any row is “1” or “−1”;
Of the N rows and N columns matrix,
Each one-row N-column submatrix that does not overlap the intermediate submatrix includes one element that is “1” or “−1” and (N−1) elements that are “0”. Mochi,
All the N rows and 1 column sub-matrices that do not overlap the intermediate sub-matrix each have one element that is “1” or “−1” and (N−1) elements that are “0”. Have
Input device. In the N-row N-column matrix, all 1-row N-column sub-matrices that do not overlap the intermediate sub-matrix are located on the same side with respect to the main sub-matrix,
The input device according to claim 3. In the N-row N-column matrix, a part of 1-row N-column sub-matrix that does not overlap the intermediate sub-matrix and another 1-row N-column sub-matrix are located on different sides with respect to the main sub-matrix. To
The input device according to claim 3. In the N-by-N matrix, all elements other than the intermediate submatrix that are not “0” are arranged on one diagonal line,
The input device according to any one of claims 3 to 5. In the N-row N-column matrix, elements other than the intermediate submatrix are all “1” or all “−1”.
The input device according to any one of claims 3 to 6. The control unit divides an element corresponding to the intermediate submatrix in the reproduction signal level matrix by a predetermined correction coefficient to generate a corrected correction signal level matrix;
The input device according to any one of claims 3 to 7. The group of detection positions includes a reference position;
The reference position corresponds to a column of the reference element in the N-by-N matrix;
The control unit is
A signal level of the detection signal at the reference position obtained by the polarity pattern corresponding to a third partial matrix of 1 row and N columns including the first partial matrix of the N rows and N columns of matrix, and the correction signal An offset calculation process for calculating a difference between the level matrix and an element corresponding to the reference position as an offset; and
Offset correction processing for correcting an element corresponding to the detection position corresponding to the intermediate submatrix of the correction signal level matrix based on the offset, or the intermediate submatrix of the correction signal level matrix Performing an offset correction process for correcting an element other than the element corresponding to the detection position corresponding to
The input device according to claim 8. The control unit is
Offset the average value of N elements in the matrix of the difference between the matrix calculated by the product corresponding to the product of the inverse matrix of the N-row N-column matrix and the combined detection signal matrix and the correction signal level matrix Offset calculation processing to calculate as, and
Performing an offset correction process for correcting each element of the correction signal level matrix based on the offset;
The input device according to claim 2. The correction coefficient is a value obtained by rounding ((N−1) / 4) to the first decimal place and multiplying by 4.
The input device according to claim 2 or 8. The control unit, as the main sub-matrix, from the Hadamard matrix based on the Paley method in which the number of rows and the number of columns exceeds the number of rows of the main sub-matrix, the row having the maximum total value of the elements in the row direction and the column direction The input device according to any one of claims 1 to 11, wherein a matrix generated by removing and columns is used. When the main submatrix is T rows and T columns,
The main sub-matrix is a combination of T shift matrices obtained by cyclically shifting a reference matrix of 1 row and T columns by a different amount from 0 to T-1 in a fixed direction in the row direction. ,
An integer P and an integer Q are selected to satisfy P> Q and that the polynomial x ^P + x ^Q +1 is an irreducible polynomial for any number x,
T = 2 ^P −1,
When the elements of the reference matrix are called from the 0th element to the (T-1) th element in the order of arrangement, in the reference matrix,
The (P-1) th element from the 0th element is either "1" or "-1",
From the 0th element to the (P-1) th element, both “1” and “−1” are included,
If the (W−P) th element and the (W−Q) th element are the same, the Wth element is “−1”,
If the (W−P) th element is different from the (W−Q) th element, the Wth element is “1”.
The input device according to any one of claims 1 to 11. T shift matrices are arranged in the order of the amount of shift,
The input device according to claim 13. The sensor unit is
A plurality of detection elements provided corresponding to the plurality of detection positions, having a signal level according to the proximity state of the object, and the polarity being set to positive or negative according to an input drive signal A plurality of detection elements each generating the detection signal;
A drive unit that supplies the drive signal to each of the plurality of detection elements according to the control of the control unit;
The detection unit includes a group of the detection elements corresponding to the group of detection positions, and generates the combined detection signal corresponding to a sum of the group of detection signals generated by the group of detection elements. The input device according to any one of 1 to 14. The sensor unit is
At least one detection electrode;
A plurality of drive electrodes intersecting the detection electrodes;
A combined detection signal generation unit,
The detection element is a capacitor formed at an intersection of the detection electrode and the drive electrode,
The drive unit supplies the drive signal to the plurality of drive electrodes, respectively.
Between the one detection electrode and the plurality of drive electrodes, a group of the capacitors as the group of detection elements is formed,
The combined detection signal generation unit is configured to output the combined detection signal corresponding to a sum of the group of detection signals representing a capacitance of the group of capacitors in either positive or negative polarity of the plurality of detection electrodes. The input device according to claim 15, wherein the input device is generated for each. The number of drive electrodes in the sensor unit is less than the number of detection electrodes,
The input device according to claim 16. A method of controlling an input device that inputs information according to the proximity state of an object at a plurality of detection positions,
The input device detects at least one object proximity state at the group of detection positions, and generates at least one combined detection signal corresponding to the sum of the group of detection signals obtained as a result of the detection for the group of detection positions. A sensor unit having two detection units and capable of controlling the positive and negative polarities of the detection signal having a signal level according to the proximity state at each detection position;
The control method is
A group of the combined detection signals composed of the combined detection signals in which the polarity patterns that are the polarities of the group set in the group of detection signals are different from each other, the same number of the combined detection signals as the group of detection signals Controlling the sensor unit to generate a group of the combined detection signals in the detection unit;
Based on the group of combined detection signals generated by the detection unit, reproducing the signal level of the group of detection signals that is the source of the combined detection signal,
The group of detection positions in one detection unit is N, the positive or negative polarity set in the detection signal is represented by “1” or “−1”, and is not added to the combined detection signal The polarity set for the detection signal is represented by “0”, and the polarity pattern set for the group of detection signals composed of the N detection signals is represented by “1”, “−1”, and “0”. And the group of polarity patterns composed of the N polar patterns are represented in a matrix of N rows and N columns composed of the N partial matrices. When expressed,
An extended inverse matrix in which one of an element greater than “0” and an element less than “0” in the inverse matrix for the N × N matrix is replaced with “1”, and the other is replaced with “−1”. A reproduction signal level of N rows and 1 column is obtained by an operation corresponding to a product of the extended inverse matrix and an N row and 1 column composite detection signal matrix including the group of combined detection signals generated by the one detection unit. A matrix is generated,
The N-by-N matrix is
A first sub-matrix with 1 row and N columns;
(N-1) a second submatrix with rows and N columns,
The first submatrix is
One element that is “1” or “−1”;
(N-1) elements that are “0”,
In the second submatrix, the sum of the elements in any row is “0”;
The second submatrix has a main submatrix that is a submatrix with (N-1) rows (N-1) columns;
In the main submatrix, the sum of the elements in any row is “1” or “−1”.
Control method of input device. A method of controlling an input device that inputs information according to the proximity state of an object at a plurality of detection positions,
The input device detects at least one object proximity state at the group of detection positions, and generates at least one combined detection signal corresponding to the sum of the group of detection signals obtained as a result of the detection for the group of detection positions. A sensor unit having two detection units and capable of controlling the positive and negative polarities of the detection signal having a signal level according to the proximity state at each detection position;
The control method is
A group of the combined detection signals composed of the combined detection signals in which the polarity patterns that are the polarities of the group set in the group of detection signals are different from each other, the same number of the combined detection signals as the group of detection signals Controlling the sensor unit to generate a group of the combined detection signals in the detection unit;
Based on the group of combined detection signals generated by the detection unit, reproducing the signal level of the group of detection signals that is the source of the combined detection signal,
The group of detection positions in one detection unit is N, the positive or negative polarity set in the detection signal is represented by “1” or “−1”, and is not added to the combined detection signal The polarity set for the detection signal is represented by “0”, and the polarity pattern set for the group of detection signals composed of the N detection signals is represented by “1”, “−1”, and “0”. And the group of polarity patterns composed of the N polar patterns are represented in a matrix of N rows and N columns composed of the N partial matrices. When expressed,
An extended inverse matrix in which one of an element greater than “0” and an element less than “0” in the inverse matrix for the N × N matrix is replaced with “1”, and the other is replaced with “−1”. A reproduction signal level of N rows and 1 column is obtained by an operation corresponding to a product of the extended inverse matrix and an N row and 1 column composite detection signal matrix including the group of combined detection signals generated by the one detection unit. A matrix is generated,
The matrix of N rows and N columns includes an intermediate submatrix of M rows and M columns;
The intermediate submatrix is
A first submatrix with 1 row and M columns;
(M-1) a second submatrix with rows and M columns,
The first submatrix is
One reference element that is “1” or “−1”;
(M-1) elements that are “0”,
In the second submatrix, the sum of the elements in any row is “0”;
The second submatrix has a main submatrix that is a submatrix of (M-1) rows (M-1) columns;
In the main submatrix, the sum of the elements in any row is “1” or “−1”;
Of the N rows and N columns matrix,
Each one-row N-column submatrix that does not overlap the intermediate submatrix includes one element that is “1” or “−1” and (N−1) elements that are “0”. Mochi,
All the N rows and 1 column sub-matrices that do not overlap the intermediate sub-matrix each have one element that is “1” or “−1” and (N−1) elements that are “0”. Have
Control method of input device.   A program for causing a computer to execute the control method for an input device according to claim 18 or 19.

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