WO2014129091A1

WO2014129091A1 - Touch panel controller, integrated circuit, touch panel device, and electronic apparatus

Info

Publication number: WO2014129091A1
Application number: PCT/JP2013/085158
Authority: WO
Inventors: 雄亮金澤
Original assignee: シャープ株式会社
Priority date: 2013-02-25
Filing date: 2013-12-27
Publication date: 2014-08-28

Abstract

A touch panel controller (10) according to an aspect of the present invention comprises: a drive unit (110) which subjects capacitors (Cji) to K iterations of parallel driving according to one M-dimensional vector of N M-dimensional vectors, and outputs K linear sum signals from sense lines (SLi); signal processing units (140) which generate noise reduction linear sum signals; and inner product computation units (150) which, by inner product computation of the noise reduction linear sum signals and the N M-dimensional vectors, estimate the value of M capacitors.

Description

Touch panel controller, integrated circuit, touch panel device, and electronic device

The present invention relates to a touch panel controller and an integrated circuit in which the touch panel controller is integrated. The present invention also relates to a touch panel device including a touch panel controller and an electronic device including the touch panel controller.

As a device for detecting capacitance values distributed in a matrix, the distribution of capacitance values in a capacitance matrix formed between M drive lines and L sense lines is detected ( A touch panel device to be estimated) is disclosed in Patent Document 1. In the touch panel device described in Patent Document 1, when the user touches the touch panel with a finger, a pen, or the like, the user detects a change in capacitance value (for example, becomes smaller) at the touched position. Detects the touched position on the touch panel.

Japanese Patent Publication “Patent No. 4927216 (issued on May 9, 2012)”

Here, the touch panel system 51 described in Patent Document 1 will be described with reference to FIG. FIG. 6 is a circuit diagram showing a configuration of the touch panel system 51 according to Patent Document 1. As shown in FIG.

The touch panel system 51 includes a touch panel 52 and a touch panel controller 53. On the touch panel 52, capacitances C11 to C44 are formed at positions where the drive lines DL1 to DL4, the sense lines SL1 to SL4, and the drive lines DL1 to DL4 and the sense lines SL1 to SL4 intersect.

The touch panel controller 53 is provided with a drive unit 54. The drive unit 54 is expressed by equation (1).

The drive lines DL1 to DL4 are driven based on the orthogonal code sequence of 4 rows and 4 columns shown in FIG. The element of the orthogonal code sequence is either “1” or “−1”. The drive unit 54 applies the voltage Vdrive when the element of the orthogonal code sequence is “1”, and applies −Vdrive when the element is “−1”. The voltage Vdrive may be a power supply voltage, for example, but may be a voltage other than the power supply voltage.

The term “orthogonal code sequence” means that a code sequence N having a code length N = (di1, di2,..., DiN) (i = 1,..., M) satisfies the following conditions. To do.

An example of the “orthogonal code sequence” is a Hadamard matrix generated by the sylvester method. The Hadamard matrix by the Sylvester method creates a basic unit of 2 rows and 2 columns as a basic structure. The upper right, upper left, and lower left bits of the basic unit are the same, and the lower right is an inversion of these bits. Next, a basic element of 2 rows and 2 columns is set as one block and arranged at the upper right, the upper left, the lower right, and the lower left, respectively, to create a code of a bit array of 4 rows and 4 columns. Here, similarly to the basic unit of 2 rows and 2 columns, the lower right block is bit-inverted with respect to the other blocks.

In the same procedure, a bit array code of 8 rows and 8 columns and 16 rows and 16 columns is generated. Such a matrix is an example satisfying the definition of the “orthogonal code sequence”. The 4-by-4 orthogonal code sequence shown in Equation (1) is a 4-row × 4-column Hadamard matrix by the Sylvester method.

The Hadamard matrix is a square matrix whose elements are either 1 or -1 and whose rows are orthogonal to each other. That is, any two rows of the Hadamard matrix represent vectors that are perpendicular to each other.

The above-mentioned “orthogonal code sequence” can use a matrix obtained by arbitrarily extracting N rows from an M-dimensional Hadamard matrix (where N ≦ M). Further, a Hadamard matrix by a method other than the Sylvester method can be applied as follows.

The N-dimensional Hadamard matrix by the Sylvester method is a power of M = 2, but there is a prediction that the Hadamard matrix exists if M is a multiple of 4. For example, there is a Hadamard matrix when M = 12, and when M = 20. A Hadamard matrix by a method other than the Sylvester method can also be used as an orthogonal code sequence.

The touch panel system 51 has four amplifiers 55 arranged at positions corresponding to the sense lines SL1 to SL4, respectively. The amplifier 55 receives and amplifies the linear sum signals Y1, Y2, Y3, and Y4 output from the capacitance sense line driven by the drive unit.

For example, the drive unit 54 applies the voltage Vdrive to all the drive lines DL1 to DL4 in the first drive among the four times of the four-row, four-column orthogonal code sequence. At this time, the measured value Y1 output from the sense line SL3 expressed by the following equation (2) is amplified by the amplifier 55.

Next, in the second drive, the drive unit 54 applies the voltage Vdrive to the drive lines DL1 and DL3, and applies -Vdrive to the drive lines DL2 and DL4. At this time, the measured value Y2 output from the sense line SL3 expressed by the following formula (3) is amplified by the amplifier 55.

Further, in the third drive, the drive unit 54 applies the voltage Vdrive to the drive lines DL1 and DL2, and applies -Vdrive to the drive lines DL3 and DL4. As a result, the measured value Y3 output from the sense line SL3 is amplified by the amplifier 55. Further, in the fourth drive, the drive unit 54 applies the voltage Vdrive to the drive lines DL1 and DL4, and applies −Vdrive to the drive lines DL2 and DL3. As a result, the measured value Y4 output from the sense line SL3 is amplified by the amplifier 55.

With the above configuration, the capacitances C31 to C34 of the touch panel system 51 shown in FIG. 6 are estimated by the following equations (4) and (5). Specifically, as shown in Expression (4), by performing an inner product calculation of the measurement values Y1, Y2, Y3, and Y4 and the orthogonal code sequence, as shown in Expression (5), the capacitance C1 ~ C4 can be estimated.

In the formulas (1), (4), and (5), the capacitances C31 to C34 are indicated by C1 to C4 for simplification of explanation. Further, for simplification of description, the coefficient (−Vdrive / Cint) is omitted for the measured values Y1 to Y4.

However, the above-described technique described in Patent Document 1 has a problem that when noise is mixed in the measured value Y, the estimation of the capacitance value of the capacitance becomes inaccurate. For this reason, in the technique described in Patent Document 1, when noise is mixed in the measurement value Y, it is difficult to operate the touch panel controller satisfactorily.

The object of the present invention has been made in view of the above problems, and its main object is to provide a touch panel controller capable of more accurately estimating the capacitance.

In order to solve the above-described problem, the touch panel controller according to one embodiment of the present invention includes M drive lines (M is an integer of 2 or more) and M sense lines formed between one sense line and the M drive lines. Capacitance is driven in parallel by N M-dimensional vectors (N is an integer and M <N), and a linear sum signal based on the charges accumulated in the M capacitances is output from the sense line. A touch panel, and an inner product operation unit that estimates a value of the M capacitances by an inner product operation of the linear sum signal output from the sense line and the N M-dimensional vectors. The controller, wherein the drive unit drives the capacitance in parallel K times (K is an integer of 2 or more) by one M-dimensional vector of the N M-dimensional vectors, and the sense K pieces from the line A signal processing unit that outputs a shape sum signal and generates a noise-reduced linear sum signal in which noise mixed in the linear sum signal is reduced based on a reference value derived from the K linear sum signals; The inner product calculation unit estimates the value of the M electrostatic capacitances by an inner product calculation of the noise-reduced linear sum signal generated by the signal processing unit and the N M-dimensional vectors.

According to the above configuration, the signal processing unit derives a reference value from the K linear sum signals output from the sense line by the driving unit, and mixes in the linear sum signal based on the reference value. A noise-reduced linear sum signal in which the generated noise is reduced is generated. The inner product calculation unit uses the noise-reduced linear sum signal for inner product calculation with the N M-dimensional vectors when estimating the M capacitance values.

In this way, the inner product calculation unit estimates the capacitance using the noise-reduced linear sum signal in which noise mixed in the linear sum signal is reduced. An error from the capacity can be reduced. Accordingly, the touch panel controller can more accurately estimate the capacitance.

It is a circuit diagram showing the composition of the touch panel device concerning one embodiment of the present invention. It is a figure which shows an example of the code series input into the drive part which concerns on one Embodiment of this invention. It is a graph which shows the signal characteristic with respect to the frequency | count of an electrostatic capacitance drive in a certain time in the touchscreen apparatus which concerns on one Embodiment of this invention. It is a graph which shows the characteristic of the estimation result of the electrostatic capacitance in the touch panel device concerning one embodiment of the present invention. It is a block diagram which shows the principal part structure of the mobile telephone which concerns on one Embodiment of this invention. It is a circuit diagram which shows the structure of the touchscreen apparatus which concerns on patent document 1.

<Embodiment 1>
A touch panel device according to an embodiment of the present invention will be described below with reference to FIGS. However, unless otherwise specified, the configuration described in this embodiment is not merely intended to limit the scope of the present invention, but is merely an illustrative example.

[Configuration of touch panel device]
First, the configuration of the touch panel device 1 according to the present embodiment will be described with reference to FIG. FIG. 1 is a circuit diagram showing a configuration of a touch panel device 1 according to the present embodiment.

As shown in FIG. 1, the touch panel device 1 includes a touch panel controller 10 and a touch panel 20.

(Touch panel)
The touch panel 20 receives a user's touch operation.

The touch panel 20 includes M drive lines DL1 to DLM arranged parallel to each other at a predetermined interval, and L lines arranged at predetermined intervals in parallel to each other so as to be orthogonal to the drive lines DL1 to DLM. Sense lines SL1 to SLL. Further, between each of the M drive lines DL1 to DLM and each of the L sense lines SL1 to SLL, the capacitance Cji (j = 1 to M, i, in a matrix of M rows × L columns). = 1 to L).

(Touch panel controller)
The touch panel controller 10 controls driving of the touch panel 20. Further, the touch panel controller 10 detects a user touch operation on the touch panel 20 and a position on the touch panel 20 touched by the user.

As shown in FIG. 1, the touch panel controller 10 includes a drive unit 110, an amplifier 120, an AD conversion unit 130, a signal processing unit 140, and an inner product calculation unit 150.

Note that the touch panel controller 10 may be realized by a single integrated circuit. Thereby, the space in the touch panel apparatus 1 for mounting the touch panel controller 10 can be minimized.

(Drive part)
The drive unit 110 includes M drive lines DL1 to DLM included in the touch panel 20 (M is an integer of 2 or more) and one sense line SLi (i = 1 to L). The electrostatic capacitances C1i to CMi are driven in parallel by N M-dimensional vectors (code sequences). Thus, the driving unit 110 outputs a linear sum signal based on the charges accumulated in the M electrostatic capacitors C1i to CMi from the certain one sense line SLi.

Specifically, code sequences D1 to DM having a sequence length N having a low correlation with each other are input to the drive unit 110. The drive unit 110 switches the value of the voltage to be applied to each of the M drive lines DL1 to DLM N times according to each value of the input code series D1 to DM. Details of the code sequences D1 to DM input to the drive unit 110 will be described later.

Further, when the value of the code sequence Dj (j = 1 to M) is “1”, the drive unit 110 applies the voltage “Vdrive” to the corresponding drive line DLj, and the value of the code sequence Dj is “−”. In the case of “1”, the voltage “−Vdrive” is applied to the corresponding drive line DLj.

As described above, the driving unit 110 switches the voltages to be applied to the M drive lines DL1 to DLM according to the input code sequences D1 to DM, and drives the M capacitances C1i to CMi in parallel. . Accordingly, the driving unit 110 outputs a linear sum signal based on the charges accumulated in the M electrostatic capacitances C1i to CMi from a certain sense line SLi.

Further, the driving unit 110 sets the capacitances C1i to CMi K times (K is 2 or more) by one M-dimensional vector among N M-dimensional vectors (N is an integer and M <N). (Integer integer) is driven in parallel, and a linear sum signal is output K times from a single sense line SLi.

(amplifier)
The amplifier 120 amplifies the linear sum signal output from the connected sense line SLi.

As shown in FIG. 1, the sense lines SL1 to SLL are connected to corresponding amplifiers 120 (1) to 120 (L), respectively. Each of the amplifiers 120 (1) to 120 (L) amplifies the linear sum signal input from the connected sense lines SL1 to SLL, and converts the amplified linear sum signal to the corresponding AD conversion unit 130 (1). To 130 (L). Hereinafter, the amplified linear sum signal output from the amplifier 120 is also referred to as an output signal OUTt.

(AD converter)
The AD conversion unit 130 converts the amplified linear sum signal input from the amplifier 120 from an analog signal to a digital signal (hereinafter also simply referred to as AD conversion).

As shown in FIG. 1, the amplifiers 120 (1) to 120 (L) are connected to corresponding AD converters 130 (1) to 130 (L), respectively. Each AD conversion unit 130 (1) to 130 (L) AD-converts the amplified linear sum signals input from the connected amplifiers 120 (1) to 120 (L), respectively, and corresponding signal processing units Output to 140 (1) to 140 (L).

(Signal processing part)
The signal processing unit 140 derives a reference value from the K output signals OUTt supplied from the amplifier 120, reduces noise mixed in the output signal OUTt based on the derived reference value (noise reduction processing), and reduces noise. Generate a linear sum signal. Details of the noise reduction processing will be described later.

The method for deriving the reference value is not particularly limited. For example, the reference value may be a median of K linear sum signals or an arithmetic average value of K linear sum signals.

The linear sum signal (noise reduced linear sum signal) subjected to noise reduction processing by the signal processing unit 140 is supplied to the inner product calculation unit 150.

(Inner product operation part)
The inner product calculation unit 150 performs an inner product calculation of the linear sum signal output from one sense line SLi and input via the amplifier 120, the AD conversion unit 130, and the signal processing unit 140, and N M-dimensional vectors. By executing, the values of the M electrostatic capacitances Ci1 to CiM are estimated.

[Noise reduction processing]
Next, noise reduction processing in the touch panel controller 10 according to the present embodiment will be described.

The sum of charges accumulated in M capacitances C1i to CMi formed between the M drive lines DL1 to DLM and one sense line SLi (that is, one sense line) Linear sum signal output from SLi)

It becomes. Further, the output signal OUTt of the amplifier 120 connected to one certain sense line SLi is

It becomes. Djt represents a code sequence input to the drive unit 110, and Cint represents the integration capacity of the amplifier 120.

For example, in order to obtain the capacitance value of the capacitance C1i for this signal, the inner product calculation unit 150 calculates the inner product of the code sequence D1t and the output signal OUTt. Specifically, the inner product calculation unit 150

Thus, the inner product calculation of the code sequence D1t and the output signal OUTt is executed. T represents the period of the code sequence.

Since the code sequences D1 to DM are “1” or “−1” as described above,

It becomes. If the correlation between the code sequences D1 to DM is 0,

Thus, the capacitance value C1i is obtained. Similarly, the inner product calculation unit 150 performs the inner product calculation with another code sequence to obtain the capacitance values C11 to CM1.

Here, when noise occurs in the touch panel device 1, that is, when noise is mixed into a linear sum signal output from a single sense line SLi, the output signal OUTt of the amplifier 120 uses the noise signal as Vnoise.

It can be expressed as.

In this case, when the inner product of the code sequence Djt and the output signal OUTt is calculated, the estimated value of the capacitance value of the capacitance C1i is

It becomes. That is, the estimated value of the capacitance value of the capacitance C1i includes

The larger the noise signal, the larger the error in the capacitance value estimation value of the capacitance C1i.

In such a case, by performing the following noise reduction processing in the signal processing unit 140, it is possible to reduce noise included in the output signal OUTt and estimate the capacitance C1i more accurately.

Independent of the driving described above, the driving unit 110 does not change the value of the code sequence (that is, by one M-dimensional vector), and does one sense line SLi (that is, the capacitances C1i to CMi). ) Is driven a plurality of times, and a linear sum signal is output a plurality of times from the one sense line SLi. The amplifier 120 amplifies a plurality of linear sum signals output from a certain sense line SLi, and outputs an output signal OUTt a plurality of times.

Here, the value of the code sequence for driving one drive line DLj in the drive unit 110 is assumed to be Dj1. Further, the number of output signals OUTt output from the amplifier 120 is K times (that is, the capacitances C1i to CMi are driven K times by one M-dimensional vector).

At this time, if the touch panel device 1 operates for a predetermined time every predetermined time, the output signal OUTt of the amplifier 120 is

It becomes. In this case, the component of the linear sum signal among the signals included in the output signal OUTt of the amplifier 120 is shown.

Is the same for each of the K output signals OUTt. The value of Vnoise indicating the noise signal component fluctuates when the noise is not low frequency noise.

The signal processing unit 140 outputs, as a reference value, the median of K output signals OUTt (one value corresponding to the center when the observation values are arranged in order of magnitude, or the arithmetic average of two values at the center). Noise reduction processing is performed on the signal OUTt. Specifically, the signal processing unit 140 reduces noise of the output signal OUTt by performing processing for removing signals having an extremely large size on the K output signals OUTt using a median filter.

For example, when K = 8, the signal processing unit 140 first rearranges the eight output signals OUTt in ascending order of values to obtain the output signal OUTBi (i = 1 to 8), and sequentially outputs the output signals in ascending order. The output signals are OUTB1 to OUTB8.

Next, the signal processing unit 140 sets the average value of the values of the fourth and fifth output signals OUTB4 and OUTB5 counted from the smallest value of the rearranged output signals OUTBi as the “reference value”. Filter. Further, the signal processing unit 140 performs filtering by replacing the output signal OUTBi having a value 20% or more larger than the reference value or the output signal OUTBi having a value smaller by 20% or more with the reference value.

The signal processing unit 140 outputs the output signal OUTt subjected to the noise reduction processing as described above to the inner product calculation unit 150 as the noise reduction linear sum signal OUTCi (i = 1 to 8). Note that the noise-reduced linear sum signal OUTCi is

Given in.

As described above, the signal processing unit 140 uses the median of the K output signals OUTt as the reference value, thereby being influenced by the output signal OUTt in which extremely large noise is mixed among the K output signals OUTt. A noise-reduced linear sum signal can be generated and output.

(Effect of noise reduction processing)
Next, the noise reduction effect in the touch panel device 1 when the signal processing unit 140 performs noise reduction processing on the output signal OUTt of the amplifier 120 as described above will be described with reference to FIGS. explain.

Here, it is assumed that the number of sense lines SLi is 1, the number of drive lines DLj is 5, and an orthogonal M sequence having a sequence length of 16 (that is, 16 five-dimensional vectors) is used as the code sequence Dj. An example of an orthogonal M sequence having a sequence length of 16 is shown in FIG. FIG. 2 is a diagram illustrating an example of a code sequence input to the drive unit 110 according to the present embodiment.

Also, the capacitances C11 to C51 are

The integration capacitance Cint of the amplifier 120 is 1 (pF), and the voltage Vdrive is 1 (V).

FIG. 3 shows the output signal OUTt output from the amplifier 120 and the noise-reduced linear sum signal output from the signal processing unit 140 in the touch panel device 1 according to the present embodiment. FIG. 3 shows the number of times t (times) of driving of the capacitance C1i at a certain time in the touch panel device 1 according to the present embodiment (where t is the subscript “t” in the output signal OUTt (that is, the electrostatic capacity of the driving unit 110) 6 is a graph showing signal characteristics with respect to the number of times of driving of the capacitor C1i).

In FIG. 3, a dotted line A1 indicates the characteristic of the output signal OUTt of the amplifier 120 with respect to the number of times t of driving of the capacitance C1i at a certain time. A solid line A2 indicates the characteristic of the noise-reduced linear sum signal OUTCi of the signal processing unit 140 with respect to the number of driving times t of the capacitance C1i at a certain time.

As shown in FIG. 3, the output signal OUTt of the amplifier 120 includes noise, and the signal value fluctuates greatly every time the capacitance C1i is driven. In contrast, the signal processing unit 140 can generate and output a noise-reduced linear sum signal OUTCi with reduced noise by performing noise reduction processing on the output signal OUTt.

In addition, the value of the actual capacitance Cji, the value of the capacitance Cji estimated by the inner product operation of the output signal OUTt and the code sequence Dj, and the inner product operation of the noise reduction linear sum signal OUTCi and the code sequence Dj are estimated. The values of the capacitance Cji thus obtained are shown in FIG. FIG. 4 is a graph illustrating characteristics of the estimation result of the capacitance Cji in the touch panel device 1 according to the present embodiment.

In FIG. 4, a solid line A3 indicates actual values of the capacitances C11 to C15 formed between the drive lines DL1 to DL5 and one sense line SL1. A dotted line A4 indicates the values of the capacitances C11 to C15 estimated by the inner product calculation of the output signal OUTt and the code sequence Dj. An alternate long and short dash line A5 indicates the values of the capacitances C11 to C15 estimated by the inner product calculation of the noise reduction linear sum signal OUTCi and the code sequence Dj.

As shown in FIG. 4, the estimation result when the capacitance Cji is estimated by the inner product operation of the output signal OUTt and the code sequence Dj is as follows:

It becomes. The estimation result when the capacitance Cji is estimated by the inner product operation of the noise reduction linear sum signal OUTCi and the code sequence Dj is as follows:

It becomes.

As illustrated in FIG. 4, the touch panel device 1 according to the present embodiment performs noise reduction processing on the output signal OUTt in the signal processing unit 140, thereby obtaining an actual capacitance Cji and an estimated capacitance Cji. The error can be reduced. Therefore, the touch panel controller 10 included in the touch panel device 1 according to the present embodiment can estimate the capacitance more accurately.

In this embodiment, the case where the code sequence is an orthogonal sequence has been described as an example. However, the present invention is not limited to this. For example, the code sequence may be an M sequence, a Gold sequence, a bulk sequence, or the like.

<Embodiment 2>
In the first embodiment, the driving unit 110 has been described by taking as an example a configuration in which the capacitance Cji is driven K times continuously by one M-dimensional vector out of N M-dimensional vectors. Is not limited to this.

For example, in the first embodiment, K = 8, but when noise is concentrated in a short time, noise is mixed in all eight output signals OUTt output from the amplifier 120, and signal processing is performed. The case where the effect of the noise reduction process in the part 140 is not sufficiently obtained can be considered.

The drive unit 110 in the touch panel device 1 according to the present embodiment includes two consecutive code sequences Dj1 and Dj2 (that is, one M-dimensional vector out of N M-dimensional vectors and another one A plurality of output signals OUTt are obtained for each of the code sequences Dj1 and Dj2 using an (M-dimensional vector).

Here, it is assumed that K output signals OUTt are obtained from the code sequence Dj1 and K output signals OUTt are obtained from the code sequence Dj2 in accordance with the driving of the touch panel 20 by the drive unit 110. At this time, the output signal OUTt of the amplifier 120 is

It becomes. That is, the amplifier 120 according to the present embodiment includes the K output signals OUTt (OUTt, OUTt + 2, OUTt + 4,..., OUTt + 2K−2) based on the code sequence Dj1, and the K output signals OUTt (OUTt + 1, OUTt + 3) based on the code sequence Dj2. ,..., OUTt + 2K−1) are output.

As described above, the driving unit 110 drives the electrostatic capacitance Cji with one code sequence Dj1 discontinuously by driving the electrostatic capacitance Cji alternately using the two code sequences Dj1 and Dj2. Will be done. As a result, the period during which the signal processing unit 140 acquires the output signal OUTt from the amplifier 120 via the AD conversion unit 130 is from t to t + 2K−1, and the capacitance Cji is driven by only one code sequence Dj1. It becomes longer than the period (from t to K-1).

Therefore, even when noise is concentrated in a short time, it is possible to prevent noise from being mixed into all output signals OUTt. Thereby, the touch panel device 1 according to the present embodiment can appropriately perform the noise reduction processing of the output signal OUTt in the signal processing unit 140 even when noise is concentrated in a short time. Thereby, the touch panel controller 10 included in the touch panel device 1 according to the present embodiment can reduce an error between the actual electrostatic capacitance Cji and the estimated electrostatic capacitance Cji. The touch panel controller 10 can more accurately estimate the capacitance.

In the present embodiment, the case where the driving unit 110 alternately drives the capacitance Cji with the two code sequences Dj1 and Dj2 has been described as an example. However, the present invention is not limited to this. For example, the driving unit 110 may drive the electrostatic capacitance Cji a predetermined number of times by the code sequence Dj1, and then drive the electrostatic capacitance Cji a predetermined number of times by the code sequence Dj2, and alternately repeat this.

In the present embodiment, the configuration in which the capacitance Cji is driven by two consecutive code sequences Dj1 and Dj2 has been described as an example. However, the present invention is not limited to this. For example, the capacitance Cji may be driven using two non-consecutive code sequences such as code sequences Dj1 and Dj3, or, for example, three or more code sequences Dj1, Dj2, and Dj4. The electrostatic capacitance Cji may be driven using the code sequence.

In the present embodiment, the configuration in which the capacitance Cji is driven K times by each of the two code sequences Dj1 and Dj2 has been described as an example. However, the present invention is not limited to this. For example, before the electrostatic capacitance Cji is driven K times by the code sequence Dj1, at least K + A electrostatic capacitances Cji are driven in parallel, of which A times (A is an integer of 2 or more) are electrostatic capacitances by the code sequence Dj2. What is necessary is just to drive Cji.

<Embodiment 3>
In the first embodiment, the configuration in which the signal processing unit 140 performs noise reduction processing using the median of the K output signals OUTt of the amplifier 120 as a reference value has been described as an example. However, as described above, K output The arithmetic average of the signal OUTt may be used as the reference value.

The value of the code sequence for driving one drive line DLj in the drive unit 110 is Dj1, and the output signal OUTt of the amplifier 120 is obtained K times (that is, one of M M-dimensional vectors). Capacitances C1i to CMi are driven K times by M-dimensional vectors).

At this time, assuming that the touch panel device 1 operates for a predetermined time every predetermined time, the output signal OUTt of the obtained amplifier 120 is the same as in the first embodiment.

It becomes. The arithmetic average of the K output signals OUTt, that is, the reference value is

Given in.

Furthermore, when an output signal OUTl is replaced with the above reference value,

Is established, the signal processing unit 140 according to the present embodiment can reduce the noise of the output signal OUTt of the amplifier 120 using the arithmetic average of the K output signals OUTt as a reference value.

Thereby, the touch panel controller 10 included in the touch panel device 1 according to the present embodiment can reduce an error between the actual capacitance Cji and the estimated capacitance Cji. The capacity can be estimated more accurately.

<Embodiment 4>
Next, as an example of an electronic apparatus including the touch panel device 1 according to the first embodiment, a mobile phone 300 will be described with reference to FIG. FIG. 5 is a block diagram showing a main configuration of the mobile phone 300 according to the present embodiment.

[Configuration of mobile phone]
As shown in FIG. 5, the mobile phone 300 according to the present embodiment includes a touch panel device 1, a CPU 310, a ROM 311, a RAM 312, a camera 313, a microphone 314, a speaker 315, an operation key 316, a display control circuit 317, and a display panel 318. It has. The components of the mobile phone 300 are connected to each other by a data bus.

The touch panel device 1 includes a touch panel controller 10 and a touch panel 20. Note that the touch panel device 1 (the touch panel controller 10 and the touch panel 20) included in the mobile phone 300 according to the present embodiment is the same as the touch panel device 1 according to the first embodiment, and thus description thereof is omitted here.

The CPU 310 comprehensively controls the operation of the mobile phone 300. For example, the CPU 310 controls the operation of the mobile phone 300 by executing a program stored in the ROM 311.

A ROM (Read Only Memory) 311 is a readable and non-writable memory that stores fixed data such as a program executed by the CPU 310 such as an EPROM (Erasable Programmable Read-Only Memory).

A RAM (Random Access Memory) 312 is a readable and writable memory, such as a flash memory, in which variable data such as data referred to by the CPU 310 for calculation or data generated by the CPU 310 is stored. .

The operation key 316 receives an instruction input from the user to the mobile phone 300. Data input via the operation key 316 is stored in the RAM 312 in a volatile manner.

The camera 313 shoots a subject based on a shooting instruction input by the user via the operation key 316. Image data of a subject photographed by the camera 313 is stored in the RAM 312 or an external memory (for example, a memory card).

The microphone 314 receives user's voice input. The input voice data (analog data) indicating the voice of the user is converted into digital data in the mobile phone 300 and sent to another mobile phone (communication partner).

The speaker 315 outputs sound represented by music data stored in the RAM 312 or the like, for example.

The display control circuit 317 drives the display panel 318 to display an image represented by the image data stored in the ROM 311 or the RAM 312 based on a user instruction input via the operation key 316. The display panel 318 may be provided so as to overlap the touch panel 20, or may include the touch panel 20, and the configuration thereof is not particularly limited.

Further, the mobile phone 300 may further include an interface (IF) (not shown) for wired connection with other electronic devices.

Since the mobile phone 300 according to the present embodiment includes the touch panel device 1, it is possible to estimate the capacitance more accurately, and thus it is possible to operate the touch panel controller satisfactorily. Therefore, since the mobile phone 300 can recognize the touch operation by the user more accurately, the mobile phone 300 can more accurately execute the process desired by the user.

[Summary]
As described above, the touch panel controller 10 according to the first aspect of the present invention includes the M static lines formed between the M drive lines DLj (M is an integer of 2 or more) and one sense line SLi. The capacitances C1i to CMi are driven in parallel by N M-dimensional vectors (N is an integer and M <N), and a linear sum signal based on the charges accumulated in the M capacitances C1i to CMi is obtained. The values of the M capacitances C1i to CMi are calculated by an inner product calculation of the driving unit 110 that outputs the sense line SLi and the linear sum signal output from the sense line SLi and the N M-dimensional vectors. The touch panel controller 10 includes an inner product calculation unit 150 for estimation, wherein the driving unit 110 uses a single M-dimensional vector of the N M-dimensional vectors to calculate a previous value. Capacitances C1i to CMi are driven in parallel K times (K is an integer of 2 or more), K linear sum signals are output from the sense lines SLi, and a reference value derived from the K linear sum signals And a signal processing unit 140 that generates a noise-reduced linear sum signal in which noise mixed in the linear sum signal is reduced, and the inner product operation unit 150 includes a noise-reduced linearity generated by the signal processing unit 140. The values of the M electrostatic capacitances C1i to CMi are estimated by an inner product operation of the sum signal and the N M-dimensional vectors.

In the touch panel controller according to aspect 2 of the present invention, the driving unit according to aspect 1 is configured such that the capacitance is continuously paralleled K times by the one M-dimensional vector of the N M-dimensional vectors. It may be driven.

According to the above configuration, the driving unit outputs K linear sum signals continuously from the sense line. As a result, the inner product calculation unit calculates the value of the M electrostatic capacitances by calculating the inner product of the K noise-reduced linear sum signals continuously generated by the signal processing unit and the N M-dimensional vectors. Can be estimated. Therefore, the touch panel controller can more accurately estimate the capacitance based on the K linear sum signals continuously obtained from the sense lines.

In the touch panel controller according to aspect 3 of the present invention, the drive unit according to aspect 1 may drive K capacitances in parallel by one M-dimensional vector out of the N M-dimensional vectors, so that K linear Before obtaining the sum signal, the capacitances are driven in parallel at least K + A times, of which A times (A is an integer of 2 or more) is determined by another M-dimensional vector among the N M-dimensional vectors. The capacitance may be driven.

According to the above configuration, the driving unit drives the capacitance for a long period of time even when noise is mixed in the linear sum signal in a short period of time. As a result, the drive unit can output a linear sum signal that does not contain noise even when noise is mixed in most of the linear sum signals that are obtained in a short period of time.

Therefore, the touch panel controller can remove noise that is concentrated in a short time and estimate the capacitance more accurately.

In the touch panel controller according to aspect 4 of the present invention, the reference value in the aspects 1 to 3 may be a value derived by a median of the K linear sum signals.

According to the above configuration, the signal processing unit uses a value derived by a median of the K linear sum signals as the reference value. Accordingly, the signal processing unit can generate a noise-reduced linear sum signal without being affected by a linear sum signal mixed with extremely large noise among the K linear sum signals.

The integrated circuit according to aspect 4 of the present invention integrates the touch panel controller according to aspects 1 to 3.

According to the above configuration, since the touch panel controller is integrated in an integrated circuit, a space for mounting the touch panel controller can be minimized.

A touch panel device according to aspect 5 of the present invention includes the touch panel controller according to aspects 1 to 3 and a touch panel controlled by the touch panel controller.

An electronic device according to aspect 6 of the present invention includes the touch panel controller according to aspects 1 to 3 and a touch panel controlled by the touch panel controller.

In addition, it should be thought that embodiment disclosed here is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

The present invention can be suitably applied to an electronic device including a touch panel controller, such as a touch panel device, a smartphone, an electronic blackboard, and a touch panel personal computer.

DESCRIPTION OF SYMBOLS 1 Touch panel apparatus 10 Touch panel controller 20 Touch panel 110 Drive part 120 Amplifier 130 AD conversion part 140 Signal processing part 150 Inner product calculation part 300 Mobile phone (electronic device)

Claims

M capacitances respectively formed between M drive lines (M is an integer of 2 or more) and one sense line are converted into N M-dimensional vectors (N is an integer, and M < N) driving in parallel, and driving the linear sum signal based on the charges accumulated in the M capacitances from the sense line;
A touch panel controller comprising: an inner product operation unit configured to estimate the value of the M capacitances by an inner product operation of the linear sum signal output from the sense line and the N M-dimensional vectors,
The driving unit drives the capacitance in parallel K times (K is an integer equal to or greater than 2) by one M-dimensional vector among the N M-dimensional vectors, and outputs K capacitances from the sense line. Output a linear sum signal,
A signal processing unit that generates a noise-reduced linear sum signal in which noise mixed in the linear sum signal is reduced based on a reference value derived from the K linear sum signals;
The inner product calculation unit estimates the value of the M capacitances by an inner product calculation of the noise-reduced linear sum signal generated by the signal processing unit and the N M-dimensional vectors.
A touch panel controller characterized by that.
The drive unit continuously drives the capacitance in parallel K times by the one M-dimensional vector of the N M-dimensional vectors;
The touch panel controller according to claim 1.
The driving unit drives the capacitance in parallel by one M-dimensional vector of the N M-dimensional vectors to obtain K linear sum signals at least K + A times before the capacitance is obtained. In parallel drive, A times (A is an integer of 2 or more) drives the capacitance by another M-dimensional vector of the N M-dimensional vectors.
The touch panel controller according to claim 1.
The reference value is a value derived by a median of the K linear sum signals.
The touch panel controller according to any one of claims 1 to 3, wherein the touch panel controller is provided.
The touch panel controller according to any one of claims 1 to 4 is integrated.
An integrated circuit characterized by that.
The touch panel controller according to any one of claims 1 to 4,
A touch panel controlled by the touch panel controller.
A touch panel device characterized by that.
The touch panel controller according to any one of claims 1 to 4,
A touch panel controlled by the touch panel controller.
An electronic device characterized by that.