JP2015007912A - Touch panel controller and electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct the influence of parasitic capacitance present on a sense line and more accurately estimate a capacitance value.SOLUTION: Values of K capacitances (C1,1 to C2,18) are estimated by inner product operation between an addition-subtraction signal and N K-dimensional vectors, the addition-subtraction signal being obtained by performing addition-subtraction on a linear sum signal for driving the K capacitances in parallel by the N K-dimensional vectors, and the other linear sum signal for driving P capacitances (1≤P≤K) out of the K capacitances by N P-dimensional vectors.

Description

  The present invention relates to 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 K drive lines and L sense lines is detected ( A touch panel device to be estimated) is disclosed in Patent Document 1.

  The touch panel device described in Patent Document 1 detects a change (for example, a decrease) in the capacitance value at a touched position when the user touches the touch panel with a detection object such as a finger or a pen. Thus, the position on the touch panel touched by the user is detected.

Specifically, the touch panel system 100 described in Patent Document 1 includes a touch panel 101 and a touch panel controller 110 as illustrated in FIG. 13. The touch panel 101 includes four drive lines DL _{1 to} DL ₄ (K = 4) and four sense lines SL _{1 to} SL ₄ (L = 4), and the drive lines DL _{1 to} DL ₄ . the position where the sense line _SL 1 to SL ₄ intersect, the capacitance C11~C44 are formed.

The touch panel controller 110 and driver 111 is provided, the driving unit 111 drives the drive line _DL 1 through DL ₄ based on the code sequence. Specifically, as shown in FIG. 14, the code sequence uses an M-sequence code that is a binary pseudorandom number sequence having a sequence length N = 31.

Here, a description will be given on the assumption that Drives 1 to 4 are assigned among the code sequences of sequence length N = 31 shown in FIG. 14 as signals for driving drive lines DL _{1 to} DL ₄ . The code sequence element is either “1” or “−1”.

  The drive unit 111 applies the voltage “Vdrive” shown in FIG. 13 when the code sequence element is “1”, and the voltage “−Vdrive” when the code sequence element is “−1”. Apply.

The touch panel system 100 includes two differential amplifiers 112 connected to the sense lines SL ₁ and SL ₂ and the sense lines SL ₃ and SL ₄ . Differential amplifier 112, when the drive unit 111 drives the drive line _DL 1 through DL _4, each electrostatic capacitance C11~C14 outputted from the sense line _{SL 1 ~SL 4, C21~C24, C31~C43} , A linear sum signal based on C41 to C44 is received and the difference is amplified.

  Here, the operation of the touch panel system 100 will be described by taking the operation of the differential amplifier 112 to which the sense lines SL3 and SL4 are connected as an example.

  The drive part 111 drives a drive line by four Drive1-4 among Drive1-31 shown in FIG.

For example, the drive unit 111 applies the voltage “Vdrive” to the drive lines DL ₁ , DL ₃ , DL ₄ and applies the voltage “−Vdrive” to the drive line DL ₂ in the drive by the 1st Vector shown in FIG. At this time, the input / output of the differential amplifier 112 is short-circuited, and the integration capacitor Cint connected to the differential amplifier 112 is in a reset state, and is operated so that the voltages of all the sense lines become zero. That is, assuming that the charges accumulated in the capacitances C31 to C34 and C41 to C44 are Q _{31 to} Q ₃₄ and Q _{41 to} Q ₄₄ , respectively, Q _{31 to} Q ₃₄ , Q _{41 to} Q ₄₄ have the sense line voltage as a value. When calculating the charge amount as a reference,

Given in Note that each of the electrostatic capacitance value of each electrostatic capacitance _C11～C44, is indicated by C 11 _{-C 44.}

Next, consider a state in which the short-circuit state of the differential amplifier 112 is released. Further, the drive unit 111 is operated so that the voltages of all the drive lines become zero. When the input voltages of the differential amplifier 112 are X3 and X4, respectively, and the output voltages are Y3 and Y4, respectively, the total charges Q _Y3 and Q _Y4 accumulated in the capacitors connected to the differential amplifier 112 are

It becomes. From the law of conservation of charge,

And the output voltages Y3 and Y4 of the differential amplifier 112 are respectively

Given in

  Here, the difference between the signals Y3 and Y4 at the output terminal of the differential amplifier 112 is

It becomes.

Here, it is assumed that “C ₃₁ + C ₃₂ + C ₃₃ + C ₃₄ + C _int ” and “C ₄₁ + C ₄₂ + C ₄₃ + C ₄₄ + C _int ” are given by substantially the same capacitance C _all . That is,

Assuming

If the gain of the differential amplifier 112 is sufficiently large, X3-X4 causes substantially zero regarded, output signal Y34 ₁ of the differential amplifier 112 obtained in driving by 1st Vector shown in FIG. 13, the differential amplifier 112 It is given by the difference between the signals Y3 and Y4 at the output terminal,

Can be written.

Of the code sequences shown in FIG. 14, the code sequence used for the i-th drive given to the drive lines DL _{1 to} DL ₄ , that is, Drive ₁ , Drive 2, Drive 3, and Drive ₄ of the i th Vector shown in FIG. Assuming Di3 and Di4, the output signal Y34 _i of the differential amplifier 112 is

Given in

By driving from the 1st vector shown in FIG. 14 to the 31th vector, 31 signals Y34 _{1 to} Y34 ₃₁ are obtained. By executing an inner product operation of the ₃₁ signals Y34 _{1 to} Y34 ₃₁ and four code lengths 31 of code sequences given to the respective drive lines DL _{1 to} DL ₄ , static signals connected to the drive lines are obtained. Capacitance can be estimated.

For example, using the sequence _{"D i1"} used to drive the drive line DL _1, when estimating the capacitance C31-C41, represented by the following formula.

  Here, it is known that the inner product between the same sequences takes the same value as the sequence length, and the inner product between different sequences takes a value of −1. Therefore, the above formula is

It becomes.

Here, it is assumed that all of the sense lines SL _{1 to} SL ₄ and all of the drive lines DL _{1 to} DL ₄ are formed with a uniform width, and the capacitance values C of the respective capacitances C 31 to C 44. if ₃₁ -C ₄₄ are substantially the same value, since the coefficient applied to the electrostatic capacitance C31-C41 is 31 times larger than the other capacitances C32-C42, C33-C43, C34-C44, other static The influence of the capacitances C32-C42, C33-C43, C34-C44 is so small that it can be ignored.

And can be simplified, it is possible to estimate the electrostatic capacitance value _C 31 _{-C 41} of the electrostatic capacitance C31-C41.

JP2013-3603A (released on January 7, 2013)

  By the way, in the conventional touch panel system 100 disclosed in Patent Document 1, the capacitance between the sense line and the drive line is reduced due to the fact that the drive line and the sense line are not uniformly arranged due to the influence of the manufacturing process. It deals with correcting for non-constant cases.

However, apart from such a problem, the parasitic capacitances Cp1 to Cp4 as shown in FIG. 13 (parasitic capacitances Cp1 and Cp2 are omitted in FIG. 13) are attached to the input of the differential amplifier 112. An error may occur in the estimated values of the capacitance values C _{11 to} C ₄₄ due to the influence of Cp 1 to Cp 4.

Here, if the parasitic capacitance Cp3, Cp4 is present, the charge stored in the capacitance obtained in the driving by _{1st Vector C 31 ~C 34, C} 41 ~C 44, a short-circuit state of the differential amplifier 112 The total charges Q _Y3 and Q _Y4 in the state of being released and operated so that the voltages of all the drive lines DL _{1 to} DL ₄ become zero are respectively

It becomes. Therefore, the output voltages Y3 and Y4 of the differential amplifier 112 are respectively

It becomes.

Similarly to the above, it is assumed that “C ₃₁ + C ₃₂ + C ₃₃ + C ₃₄ + C _int ” and “C ₄₁ + C ₄₂ + C ₄₃ + C ₄₄ + C _int ” are given by substantially the same capacitance C _all . Similarly to the above, when the gain of the differential amplifier 112 is sufficiently large, if X3-X4 can be regarded as substantially zero,

It becomes.

Similarly to the above, if Drive1, Drive2, Drive3, and Drive4 of it Vector are set to Di1, Di2, Di3, and Di4, respectively, the output Y34 _i of the differential amplifier 112 is

Given in.

Here, X3 _i and X4 _i are considered. When it is assumed that Drive 1, Drive 2, Drive 3, and Drive 4 of it Vector are D _i1 , D _i2 , D _i3 , and D _i4 , respectively,

When this is summarized for X3 _i and X4 _i ,

It becomes. The signals Y3 _i and Y4 _{i at} the respective output terminals of the differential amplifier 112 are obtained by using the output signal Y34 _i of the differential amplifier 112 and the common mode voltage Vcm.

Can be written. Therefore,

And can be transformed. To simplify the formula,

Let Q _tot be expressed as In this case, the above formula is

It becomes.

  Organizing X3i and X4i respectively

It becomes.

From these, when X3 _i is obtained,

Similarly, for X4 _i ,

Given in

Consider the influence of the X3 _i and X4 _i on the output signal Y34 _i . The output signal Y34 _i is

Given in.

Here, when it is assumed that the capacitance values C _{31 to} C _{44 of the} capacitances C _{31 to} C ₄₄ are all the same capacitance value Cx,

It becomes. Here, assuming that Vdrive and Vcm are fixed values and the capacitance is also a fixed value, the component that changes according to the signal for driving the drive line in the above equation is:

The difference Cp3-Cp4 between the parasitic capacitance Cp3 and the parasitic capacitance Cp4 is a signal proportional to the signal driven by the sum of the code series (D _i1 + D _i2 + D _i3 + D _i4 ). That is, when there is a difference in parasitic capacitance (Cp3−Cp4 ≠ 0), the charge generated by the total value of the drive patterns (here, “D _i1 + D _i2 + D _i3 + D _i4 ”) is generated in the integral capacitance Cint of the differential amplifier 112. There arises a problem that the estimation of the capacitance values C _{31 to} C ₃₄ and C _{41 to} C ₄₄ becomes inaccurate.

  For this reason, with the technique described in Patent Document 1, it becomes difficult to operate the touch panel controller satisfactorily.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to correct the influence of the parasitic capacitance existing in the sense line and more accurately estimate the capacitance value. To provide a touch panel controller and an electronic device.

  In order to solve the above-described problem, the touch panel controller according to one embodiment of the present invention uses K M capacitances formed between a sense line and K drive lines (K is a plurality) as M series codes, Driven in parallel by N K-dimensional vectors included in N Q-dimensional vectors (N is an integer, Q is an integer of 3 or more) representing a Gold series code or an orthogonal code, and stored in the K capacitances A drive unit that outputs a linear sum signal based on the charged charges from the sense line, and the drive unit uses the N P-dimensional vectors (1 ≦ P ≦ K) included in the N Q-dimensional vectors to P of the capacitances are driven in parallel, and another linear sum signal based on the charge accumulated in the P capacitances is output from the sense line, and the linear sum signal and the other capacitance are output. Addition and subtraction with linear sum signal A subtraction signal obtained Te, the inner product operation between the N K-dimensional vector, and further comprising an inner product calculation unit for estimating the value of the K electrostatic capacitance.

  An integrated circuit according to one embodiment of the present invention includes the touch panel controller described above.

  An electronic device according to one embodiment of the present invention includes the touch panel controller described above and a touch panel controlled by the touch panel controller.

  Another electronic device according to one embodiment of the present invention is configured such that K capacitances formed between a sense line and K drive lines (K is a plurality) are represented by an M-sequence code, a Gold-sequence code, or an orthogonal code. A linear sum based on the charges accumulated in the K capacitances, driven in parallel by N K-dimensional vectors included in N Q-dimensional vectors (N is an integer, Q is an integer of 3 or more) A driving unit configured to output a signal from the sense line, and the driving unit includes N P-dimensional vectors (1 ≦ P ≦ K) included in the N Q-dimensional vectors. A touch panel controller which drives P of them in parallel and outputs another linear sum signal based on the electric charge accumulated in the P capacitances from the sense line; and a touch panel controlled by the touch panel controller. And a central processing unit that receives the linear sum signal and the other linear sum signal, wherein the central processing unit receives the linear sum signal and the other linear sum signal. It includes an inner product calculation unit that estimates the value of the K electrostatic capacitances by calculating an inner product of an addition / subtraction signal obtained by addition / subtraction and the N K-dimensional vectors.

  According to one embodiment of the present invention, there is an effect of providing a touch panel controller and an electronic device that can correct the influence of parasitic capacitance existing in a sense line and more accurately estimate a capacitance value.

It is a block diagram which shows the touchscreen apparatus in Embodiment 1 of this invention, Comprising: The structure of the simple model for operation | movement description is shown. It is a block diagram which shows the whole structure of the said touchscreen apparatus. It is a figure which shows the code series which consists of M series for driving the said touchscreen apparatus. It is a figure which shows the drive1-drive16 of the Walsh code | symbol for driving the said touch panel apparatus. It is a figure which shows drive17-drive32 of the said Walsh code. It is a figure which shows the Hadamard code | symbol for driving the said touchscreen apparatus. It is a figure which shows the ternary M series for driving the said touch panel apparatus. It is a block diagram which shows the structure of the mobile telephone as an electronic device in Embodiment 3 of this invention. It is a block diagram which shows the whole structure of the touchscreen apparatus in Embodiment 4 of this invention. (A) shows the touch panel device according to the first embodiment of the present invention, in which the output signal Ys _i of the signal processing unit when there is a touch input near the intersection of the sense line SL ₁ and the drive line DL ₁₁ is shown. is a waveform diagram showing a waveform diagram showing the (b) is a linear sum signal _{Y1 i ~Y4} i when there is a touch input in the vicinity of the intersection of the sense line SL ₁ and the drive line _{DL 11.} The capacitance value when the touch input of the touch panel device in the first embodiment is present is shown, and the capacitance value when the correction process is performed is compared with the capacitance value when the correction process is not performed. It is a graph. It is a graph which shows the touch panel apparatus in Example 2 of this invention, Comprising: The difference of the effect of correction | amendment in Example 1 and Example 2 when external noise mixes. It is a block diagram which shows the structure of the conventional touch panel system. It is a figure which shows the code sequence which consists of M series for driving the said conventional touch panel system.

[Embodiment 1]
One embodiment of the present invention is described below with reference to FIGS. However, the configuration described in this embodiment is merely an illustrative example, and is not intended to limit the scope of the present invention only to that unless otherwise specified.

[Configuration of touch panel device]
The configuration of the touch panel device 1 of the present embodiment will be described with reference to FIG. FIG. 2 is a configuration diagram showing the touch panel device 1 of the present embodiment.

The touch panel device 1 according to the present embodiment includes a touch panel 2 and a touch panel controller 3 as shown in FIG. The touch panel 2 includes a driveline _DL 1 through DL _K of K book, and a sense line _SL 1 to SL _L of L present. The position where the driveline _DL 1 through DL _K and the sense line _SL 1 to SL _L intersect, capacitance C1,1～CL, K are formed. Incidentally, the capacitance C1,1～CL, each of the electrostatic capacitance value of K, respectively _C 1, 1 _{-C L,} assumed to be _K.

The sense line _SL 1 to SL _L is connected to the differential amplifier OP. The output signal of the differential amplifier OP is converted into a digital signal by the AD conversion unit 21 and then input to the inner product calculation unit 23 through the signal processing unit 22. The output signal of the inner product calculation unit 23 is an estimated value of capacitance.

The differential amplifier OP of the present embodiment is composed of a differential amplifier of differential input-differential output, and an integrating capacitor Cint is installed between the respective input-output terminals. The input terminals of the differential amplifier OP are connected to the sense lines SL ₁ and SL ₂ , for example. The output signals of the differential amplifier OP are Y1 and Y2, respectively. The AD converter 21 converts the difference Y1-Y2 in the output signal of the differential amplifier OP into a digital value.

The drive lines DL _{1 to} DL _K are connected to the drive unit 10. A drive control unit 11 is connected to the drive unit 10, and the drive control unit 11 drives the drive unit 10 to drive the K drive lines DL _{1 to} DL _K by at least two types of drive methods. It is something to control.

  Operations of the drive unit 10, the drive control unit 11, the signal processing unit 22, and the inner product calculation unit 23 in the touch panel device 1 having the above configuration will be described.

In the touch panel device 1 of this embodiment, the control of the drive control unit 11, the drive line _DL 1 through DL _K is driven by the drive unit 10, thereby, the electrostatic capacitance C1 from the sense line _SL 1 to SL _L, A linear sum signal based on 1 to C1, K to CL, 1 to CL, and K is output.

The drive unit 10 is provided with code sequences D _{1 to} D _K having low correlation with each other. When the code is “1”, the drive unit 10 applies the voltage “Vdrive” to the corresponding drive line, and the code is “− In the case of “1”, the voltage “−Vdrive” is applied to the corresponding drive line.

The signal processing unit 22 adds the digitally converted output signal of the differential amplifier OP for one period (first clock to 63rd clock) of the code series D _{1 to} D _K.

The inner product calculation unit 23 calculates the inner product between the output signal of the differential amplifier OP that has been digitally converted and the code sequences D _{1 to} D _K.

[Estimation of capacitance value of touch panel controller]
The operation of the touch panel controller 3 having the above configuration will be described below with reference to FIG. FIG. 1 shows a touch panel having two sense lines connected to one differential amplifier OP and 18 drive lines crossing the two sense lines in order to simplify the operation of the touch panel controller 3. 2 is a block diagram illustrating a configuration of a touch panel device 1A as an example of the device 1. FIG.

As shown in FIG. 1, the touch panel device 1A has two sense lines SL ₁ and SL ₂ (L = 2) and 18 drive lines DL ₁ , DL ₂ ... DL ₁₈ (K = 18). doing.

In the touch panel device 1A having the above configuration, the drive unit 10, the drive line _{DL 1,} DL 2, ..., the _{DL 18,} each drive line _{DL 1, DL 2, ...,} 18 pieces of sequence length given to the _{DL 18} The drive is performed in parallel with N (N is an integer satisfying N ≧ 18) code sequences D _{1 to} D ₁₈ . As shown in FIG. 3, the code sequences D _{1 to} D ₁₈ bit-shift an M sequence (M-sequence) that is a binary pseudorandom number sequence including a Q-dimensional vector (Q = 63) having a sequence length N = 63. The code sequence generated in this way is used.

Here, the code sequences D _{1,1 to} D ₆₃ , ₆₃ correspond to “N Q-dimensional vectors (N is an integer, Q is an integer of 3 or more)” described in the claims. Here, an example of N = Q = 63 is shown. However, the present invention is not limited to this. For example, the Walsh code of N = Q = 32 shown in FIGS. 4 and 5 can be applied to the present invention. N and Q may be different. For example, the Hadamard code of N = 32 and Q = 16 shown in FIG. 6 can be applied to the present invention. Furthermore, the ternary M series of N = 31 and Q = 15 shown in FIG. 7 can be applied to the present invention.

The code sequences D _{1,1 to} D _18,63 correspond to “N K-dimensional vectors” recited in the claims. Then, the code sequence _D 19,1 _{~D 36,63,} the code sequence _D 37,1 _{~D 54,63,} and the code sequence _D 55,1 _{~D 63,63} is "the N P of claim This corresponds to a dimension vector (1 ≦ P ≦ K).

Specifically, in the example of the code sequence shown in FIG. 3, the code sequences D _{1 to} D _K are bit-shifted for each clock to change the value, and the same value is repeated every 63 clocks. Each M sequence is assumed to be a code sequence D1 _{, i-} D63 _{, i} . That is, the code sequence D _{1, i to} D _{63, i} changes in value for each clock, becomes the value of the code sequence D _{1,1 to} D _{63,1 in} the first clock, and D _{1,63 in} the 63rd clock. It becomes the value of _-D63,63 . At the 64th clock, the code sequence D _{1,1 to} D _63,1 returns to the same value as the first clock, and the same value is repeated every 63 clocks.

The clock signal is 1 MHz. The elements of the code sequences D _{1 to} D _K , that is, the codes D _{1,1 to} D ₆₃ , ₆₃ are either “1” or “−1”.

Further, as illustrated in FIG. 1, when the elements of the code sequences D _{1 to} D ₁₈ are “1”, the driving unit 10 applies the voltage “Vdrive”, and the elements of the code sequences D _{1 to} D ₁₈ are In the case of “−1”, the voltage “−Vdrive” is applied. For example, the power supply voltage VDD is used as the voltage “Vdrive”. Further, it may be a voltage other than the power supply voltage such as a reference voltage.

The touch panel device 1A has one differential amplifier OP connected to the sense lines SL ₁ and SL ₂ . Differential amplifier OP, when the drive unit 10 drives the drive line _DL 1 _{through DL 18,} each of the electrostatic capacitance that is output from the sense line _SL 1, _{SL 2 C1,1~C1,18, C2,1~} The linear sum signals X1 and X2 based on C2 and 18 are received and the difference is amplified.

For example, the drive unit 10, the code sequence _D 1, 1 _{to D} 18,1 sequence length 63 to the drive line _DL 1 _{through DL 18,} ..., the _{D 1,63 ~D 18,63,} of the i clock code In driving by the series D _{1, i to} D _{18, i} , either the voltage “Vdrive” or the voltage “−Vdrive” is applied. At this time, the output Y1 _i -Y2 _i which is the output Y _i of the differential amplifier OP connected to the sense lines SL ₁ and SL ₂ is expressed by the following equation (1).

Given in A difference Y _i between the output signals of the differential amplifier OP is given by Y1 _i -Y2 _i .

Here, each of the electrostatic capacitance value _C 2,1 _{-C 2,18} for each of the electrostatic capacitance value _C 1, 1 _{-C 1, 18} and the sense line SL ₂ sense line SL _1, the output of the differential amplifier OP It can be estimated by executing an inner product operation of the signal “Y _i = Y1 _i −Y2 _i ” based on the signal and the 18 code sequences D _{i, 1 to} D _{i, 18} having a sequence length of 63.

For example, using the sequence _{"D i, 1"} used to drive the drive line DL _1, when estimating the capacitance value _{C 1,1-2,1} of the capacitance C1,1-C2,1, It is represented by the following formula (2).

  Here, as for M series, it is known that the inner product of the same series takes the same value as the sequence length, and the inner product of different series takes a value of -1. Therefore, the above equation (2) is

And can be simplified, it is possible to estimate the electrostatic capacitance value _{C 1,1-2,1} of the capacitance C1,1-C2,1. In Expression (3), the second term of Expression (2) is omitted.

[Operation to correct the influence of parasitic capacitance]
However, in the touch panel device 1A of the present embodiment, parasitic capacitances Cp1 to Cp2 as shown in FIG. 1 are attached to the input of the differential amplifier OP, and each capacitance value Cp is affected by the parasitic capacitances Cp1 and Cp2. _An error may occur in the estimated values of _1,1 to _C2,18 . Parasitic capacitance Cp1 is assumed to be a capacitance between the sense line SL ₁ and the ground. In addition, the parasitic capacitance Cp2 is the capacitance between the sense line SL ₂ and the ground. Each of these parasitic capacitances Cp1, Cp2 is the capacitance _C1 from the sense line _SL 1 to SL _2, the differential amplifier when the linear sum signal is output based on 1～C1,18～C2,1～C2,18 OP This affects the input signals X1 and X2.

That is, the parasitic capacitance is generated because the signal wiring has a physical shape. The signal wiring is usually made of a metal having a certain width, and this forms a capacitance with some surrounding conductor. Usually, in an electric circuit, the conductor is often grounded, so that a parasitic capacitance between the signal line and the ground is formed without aiming. The parasitic capacitance is not necessarily attached to the touch panel controller 3, but is also attached to the touch panel 2 and a substrate (not shown). Thus, in this embodiment, the parasitic capacitance Cp1 present in such sense line SL _1, is aimed at correcting the errors caused by the difference between the parasitic capacitance Cp2 present in the sense line SL _2.

If the parasitic capacitance Cp1, Cp2 are different, signals based on charge multiplying by the total value of the driving pattern is mixed into the integrating capacitor _{C int} of the differential amplifier OP, the electrostatic capacitance of the electrostatic capacitance C1,1-C2,1 There is a problem that the estimation of the values C _1,1 -C _2,1 becomes inaccurate.

  The extent of the influence when there is a difference between the parasitic capacitances Cp1 and Cp2 will be described below.

  First, since the output signal Yi of the differential amplifier OP at the time of driving the i-th clock is given by the total value of the drive pattern Di as described above, it is caused by the difference between the parasitic capacitances Cp1 and Cp2 of the differential amplifier OP. If the coefficient is a,

Given in.

It is possible to estimate the capacitance value by performing an inner product operation between the code sequence D _{i, 1} used in the drive of the output signal Yi and driveline DL _1. Here, 1 ≦ i ≦ N = 63.

For example, the capacitance value C1,1-2,1 of the capacitance C1,1- _C2,1 is

Is estimated.

  Here, as described above, when an M sequence is used as Di, the inner product between the same sequences takes the same value as the sequence length, and the inner product between different sequences takes a value of −1. Equation (5) is

It becomes.

  In equation (6), the components other than the first term are error components. Here, among the error components of the second term and the third term, whichever is larger depends on the touch panel 2 to be used, the number of sense lines, the number of drive lines, and the substrate, but the error component of the third term is dominant. It is thought that there are many cases that become empirically.

  Therefore, if, for example, the error component of the third term in equation (6) can be reduced, the effect when there is a difference between the parasitic capacitances Cp1 and Cp2 can be reduced.

  The touch panel controller 3 of the touch panel device 1A of the present embodiment has the following configuration in order to reduce the error component of the third term in the equation (6).

That is, the touch panel controller 3 of the touch panel device 1A of the present embodiment is formed at each intersection with the _two sense lines SL ₁ and SL ₂ by driving the ₁₈ drive lines DL _{1 to} DL ₁₈ in parallel. the linear sum signal based on the charge stored in the capacitance and the driving unit 10 to output from the sense line _SL 1, _{SL 2,} the parasitic capacitance Cp1, Cp2 capacitance that exists for each sense line _SL 1, SL ₂ A drive control unit 11 that controls the drive unit 10 to drive the ₁₈ drive lines DL _{1 to} DL ₁₈ in parallel by at least two types of parallel drive methods, and at least two types. An inner product calculation unit 2 that estimates the capacitance value based on the inner product calculation of the linear sum signal and the code sequence when driven in parallel by the parallel driving method of It is equipped with a door.

Thereby, even if the parasitic capacitances Cp1 and Cp2 existing for the sense lines SL ₁ and SL ₂ are different from each other, the 18 drive lines DL _{1 to} DL ₁₈ are driven in parallel by at least two types of parallel drive methods. Thus, it is possible to obtain an estimated value of each capacitance value in which the influence of the parasitic capacitances Cp1 and Cp2 is reduced.

Therefore, it is possible to provide the touch panel controller 3 that can correct the influence of the parasitic capacitances Cp1 and Cp2 existing in the sense lines SL ₁ and SL ₂ and more accurately estimate the capacitance value. ing.

  Specific processing of the correction operation of the touch panel controller 3 will be described below.

First, in the touch panel controller 3 of the present embodiment, 18 drive lines DL ₁ are generated by a second code sequence of 18 different sequence lengths 63 different from the first code sequence of 18 sequence lengths 63. ~ DL ₁₈ is driven in parallel. That is, 18 second code sequences D2 _{i, j} having a sequence length 63 different from 18 first sequence sequences D _{i, j} having 18 sequence lengths 63 are prepared.

Here for the sake of simplicity
N−K = K
To be. As a result, it is assumed that N = 2K.

That is, a second code sequence D2 _{i, j} having 18 sequence lengths 63 different from the first code sequence D _{i, j} having 18 sequence lengths 63 is used. Therefore, the second code sequence D2 _{i, j} is assumed to be an M sequence that is not the Dij used in Equation (5) among the M sequences.

The output Y2 _i of the differential amplifier OP when driven by the new second code sequence D2 _{i, j} is similar to the equation (4),

Can be obtained by:

Here, the inner product of the sum of the output signal Y _i and the output signal Y2 _i of the differential amplifier OP and the second code sequence D2 _{i, j} is calculated. Similar to equations (5) and (6),

It becomes.

  Here, since N = 2K, the third term of the above equation (7) is “a”. On the other hand, in the case of Equation (6), that is, when the capacitance value is estimated only by the conventional first parallel driving method, this term becomes “a * (K + 1)”.

  Therefore, in the touch panel controller 3 of the present embodiment, the capacitance value is estimated by the two types of parallel drive methods of the first parallel drive method and the second parallel drive method, so that the estimation error is reduced. Will be able to.

Incidentally, in the second parallel driving method, it is not always necessary to drive the 18 pieces of driveline _DL 1 _{through DL 18,} as in the fourth set shown in FIG. 3, nine driveline _DL 1 through DL ₉ May be driven. In other words, it is only necessary to drive at least one of the _K drive lines DL _{1 to} DL _K.

  The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention. For example, in the present embodiment, a case has been described in which the capacitance value is estimated by two types of parallel drive methods, the first parallel drive method and the second parallel drive method, so as to satisfy N = 2K. However, the present invention is not particularly limited to this. For example, in addition to the first parallel driving method and the second parallel driving method, the third parallel driving method, the fourth parallel driving method, etc. It is also possible to use various kinds of parallel drive methods. In Example 1 to be described later, a case where the first parallel driving method, the second parallel driving method, the third parallel driving method, and the fourth parallel driving method are used is exemplified.

Thus, the touch panel controller 3 in the touch panel device 1A of this embodiment, the drive control unit 11, 18 that 18 pieces of the driveline _DL 1 _{through DL 18,} is provided to each of the drive lines _DL 1 _{through DL 18} Are driven in parallel with a first code sequence D _{i, j having} a sequence length of 63 and a capacitance at each of 18 intersections of 18 drive lines DL _{1 to} DL ₁₈ and one sense line SL _1. a first parallel driving method of the first linear sum signal based on the accumulated charge (linear sum signal) output from the sense line SL _1, at least one or more of the above eighteen driveline DL ₁ through DL ₁₈ a sequence length 63, the first code sequence _{D i,} second code sequence _{D2 i} different from _j, and driven with _j, and one sense line SL ₁ and At least two parallel and second parallel driving method of the second linear sum signal based on the electric charges accumulated in each formed electrostatic capacitance at each intersection (other linear sum signal) output from the sense line SL ₁ The drive unit 10 is controlled so as to be driven in parallel by the drive method. Further, the inner product calculation unit 23 adds / subtracts signals obtained by adding or subtracting the first linear sum signal obtained by the first parallel driving method and the second linear sum signal obtained by the second parallel driving method. Then, the inner product calculation of the 18 first code sequences D _{i, j} having the sequence length 63 is performed to estimate 18 electrostatic capacitance values.

That is, K drive lines (K is an integer equal to or greater than 2) are converted to K sequence lengths N (N is an integer satisfying N ≧ K) given to each drive line as a first code sequence _{Di, j} . The first parallel sum signal is output from the sense line based on the charge accumulated in the electrostatic capacitance at each of the K intersections of the K drive lines and one sense line. In the driving method, in order to estimate K capacitance values, an inner product operation of the first linear sum signal and the first code sequence D _{i, j of} K sequence lengths N is performed in an inner product calculation unit. Just do it.

However, when there is a parasitic capacitance that exists for each sense line, the influence of the parasitic capacitance is as follows.
a * (N-K + 1)
It is expressed. Here, in order to reduce “a * (N−K + 1)”, it is an ideal situation that NK + 1 = 0. However, since the maximum value of K is N, even if N = K which is the best situation, N−K + 1 = 1, and at that time, the influence of the parasitic capacitance is the minimum value a * 1 = a.

  Here, since the number K of drive lines is a value determined by the touch panel, generally, the number K of drive lines cannot be controlled.

  However, the same effect as when the number K of drive lines is increased can be obtained by driving K drive lines a plurality of times and using the sum of the results as a signal. That is, by driving the K drive lines a plurality of times and increasing the apparent number K of drive lines, “a * (N−K + 1)” is reduced, and the influence of parasitic capacitance can be reduced.

Accordingly, in this embodiment, the drive control unit 11, the drive line _DL 1 through DL _K of K the first code sequence D of the respective drive line _DL 1 of K given in the through DL _K sequence length N First linearity based on charges accumulated in capacitance at each of K intersections of the K drive lines DL _{1 to} DL _K and one sense line SL _1, which are driven in parallel with _{i and j} . a first parallel driving method for outputting a sum signal from the sense line SL _1, at least one or more of the driveline DL ₁ through DL _K of the K present, the sequence length N, the first code sequence D _{i second} linear based on charge stored in different second code sequence D2 _i, driven by using the _j, and the electrostatic capacitance formed respectively at each intersection between the sense line SL ₁ of one above the _j The sum signal is It controls the driving unit 10 so as to parallel driven at least two parallel drive method of the second parallel drive method to be output from the down SL _1. The addition / subtraction obtained by adding or subtracting the first linear sum signal obtained by the first parallel driving method and the second linear sum signal obtained by the second parallel driving method in the inner product calculation unit 23 An inner product operation of the signal and the first code sequence D _{i, j of} K sequence lengths N is performed to estimate K capacitance values.

As a result, the K drive lines DL _{1 to} DL _K are driven in parallel by at least two types of parallel drive methods, ie, the first parallel drive method and the second parallel drive method. It is possible to obtain an estimated value in which the influence of the parasitic capacitances Cp1 and Cp2 is suppressed rather than the estimated value of the individual capacitance values. Therefore, the capacitance value can be estimated more accurately.

  In this embodiment, four sets of driving are performed, but the number may be smaller or larger.

  In the present embodiment, the differential amplifier OP is used as an amplifier, but a single-ended amplifier can also be used.

  Furthermore, in the present embodiment, an M-sequence code is used as a code sequence, but the present invention is not limited to this, and the Walsh code shown in FIGS. 4 and 5 and the Hadamard code (orthogonal code) shown in FIG. May be used. Furthermore, other code sequences such as Gold sequence codes can be used.

[Embodiment 2]
The second embodiment of the present invention will be described as follows. The configurations other than those described in the present embodiment are the same as those in the first embodiment. For convenience of explanation, members having the same functions as those shown in the drawings of the first embodiment are given the same reference numerals, and explanation thereof is omitted.

In the touch panel controller 3 of the first embodiment, the inner product calculation unit 23 receives the first linear sum signal obtained by the first parallel driving method and the second linear sum signal obtained by the second parallel driving method. An inner product operation is performed on an addition / subtraction signal obtained by addition or subtraction and 18 code sequences _{Di, j} having a sequence length of 63. Specifically, the capacitance value was estimated by the inner product calculation of the signal Ys _i and the code series D _{1, i to} D _{18, i} .

However, in an environment in which noise is mixed from the outside _, in addition to the code sequences D _{1, i to} D _{18, i} , the other code sequences D2 _{i, j} are also used for inner product calculation, so that noise is reduced. The impact can be reduced.

  This method will be specifically described below.

  In this case, as in equation (8),

Is obtained.

  Therefore, a larger signal can be obtained by using the result of adding these results as the capacity estimation result. Specifically, as shown in the following equation (10), a larger signal can be obtained by using the result of adding the equations (8) and (9) as the estimation result of the capacitance value.

  In addition, this invention is not limited to said embodiment, A various change is possible within the scope of the present invention. For example, in the present embodiment, a case has been described in which the capacitance value is estimated by two types of parallel drive methods, the first parallel drive method and the second parallel drive method, so as to satisfy N = 2K. However, the present invention is not particularly limited to this. For example, in addition to the first parallel driving method and the second parallel driving method, the third parallel driving method, the fourth parallel driving method, etc. It is also possible to use various kinds of parallel drive methods. In the second embodiment to be described later, the inner product of three types of code sequences is used in the four parallel driving methods of the first parallel driving method, the second parallel driving method, the third parallel driving method, and the fourth parallel driving method. Exemplifies the case of estimating the capacitance value.

  In the present embodiment, in the inner product calculation unit 23, the addition / subtraction signal is obtained by adding at least two types of linear sum signals of the first linear sum signal and the second linear sum signal. However, the present invention is not necessarily limited to this, and the addition / subtraction signal may be obtained by subtracting at least two types of linear sum signals of the first linear sum signal and the second linear sum signal.

Thus, in the touch panel controller 3 of the touch panel device 1A of the present embodiment, the inner product calculation unit 23 adds or subtracts at least two types of linear sum signals of the first linear sum signal and the second linear sum signal. A first inner product calculation result of the obtained addition / subtraction signal and the first code sequence D _{i, j of} 18 sequence lengths 63 _, and a second of the addition / subtraction signal and the second code sequence D2 _{i, j of} sequence length N Based on the result of adding the inner product calculation result, 18 electrostatic capacitance values are estimated.

That is, in the first parallel driving method, the addition / subtraction signal obtained by adding or subtracting at least two types of linear sum signals of the first linear sum signal and the second linear sum signal by the inner product calculation unit 23, The first inner product calculation result can be obtained by the inner product calculation with the first code sequence D _{i, j} having 18 sequence lengths 63 used in the driving method.

On the other hand, in the second parallel driving method, the inner product calculation unit 23 uses the second code sequence D2 _{i, j} different from the first code sequence D _{i, j} with the sequence length 63, so addition / subtraction The second inner product calculation result can also be obtained by the inner product calculation of the signal and the second code sequence D2 _{i, j of} sequence length 63.

  Therefore, 18 electrostatic capacitance values can be estimated also by adding the first inner product calculation result and the second inner product calculation result.

In particular, in an environment in which noise is mixed from the outside, the first inner product calculation based on the inner product calculation of the addition / subtraction signal and the first code sequence D _{i, j of} 18 sequence lengths 63 used in the first parallel driving method. In addition to the result, the influence of noise can be reduced by using the second inner product calculation result by the inner product calculation of the addition / subtraction signal and the second code sequence D2 _{i, j} having the sequence length 63. The noise mixed from the outside means thermal noise generated by a circuit, environmental noise mixed in touch input, or the like.

  As a result, in the case where noise is mixed from the outside, the capacitance value can be estimated more accurately.

[Embodiment 3]
The following will describe still another embodiment of the present invention with reference to FIG. The configurations other than those described in the present embodiment are the same as those in the first embodiment and the second embodiment. For convenience of explanation, members having the same functions as those shown in the drawings of Embodiment 1 and Embodiment 2 are given the same reference numerals, and explanation thereof is omitted.

  In the present embodiment, a case where the touch panel device 1 or 1A is mounted on a mobile phone as an electronic device will be described with reference to FIG. FIG. 8 is a block diagram showing the configuration of the mobile phone.

  As shown in FIG. 8, the mobile phone 60 according to the present embodiment includes a touch panel device 1, 1 </ b> A, a display panel 61, operation keys 62, a speaker 63, a microphone 64, a camera 65, a CPU 66, and a ROM 67. A RAM 68 and a display control circuit 69. Each component is connected to each other by a data bus.

  As described above, the touch panel device 1 or 1A includes the touch panel 2, the touch panel controller 3 that detects capacitance or a capacitance difference, and the stylus pen 4 as a detection target. The detected object is not necessarily limited to the stylus pen 4 and may be a finger.

  The display panel 61 displays images stored in the ROM 67 and the RAM 68 by the display control circuit 69. The display panel 61 is superimposed on the touch panel 2 or has the touch panel 2 incorporated therein.

  The operation key 62 receives an instruction input by the user of the mobile phone 60.

  The speaker 63 outputs a sound based on, for example, music data stored in the RAM 68.

  The microphone 64 receives the user's voice input. The mobile phone 60 digitizes the input voice (analog data). Then, the cellular phone 60 sends the digitized voice to a communication partner (for example, another cellular phone).

  The camera 65 captures a subject in response to the operation of the operation key 62 by the user. Note that image data of the photographed subject is stored in the RAM 68 or an external memory (for example, a memory card).

  The CPU 66 controls the operations of the touch panel devices 1 and 1A and the mobile phone 60. The CPU 66 executes a program stored in the ROM 67, for example.

  The ROM 67 stores data in a nonvolatile manner. The ROM 67 is a ROM capable of writing and erasing, such as an EPROM (Erasable Programmable Read-Only Memory) and a flash memory. Although not shown in FIG. 8, the mobile phone 60 may be configured to include an interface (IF) for connecting to another electronic device by wire.

  The RAM 68 stores data generated by the execution of the program by the CPU 66 or data input via the operation keys 62 in a volatile manner.

  As described above, the mobile phone 60 as the electronic apparatus in the present embodiment includes the touch panel device 1 or 1A. As a result, the capacitance can be estimated more accurately, and the touch panel controller 3 can be operated satisfactorily. Therefore, since the mobile phone 60 can recognize the touch operation by the user more accurately, the mobile phone 60 can more accurately execute the process desired by the user.

[Embodiment 4]
In the first to third embodiments, the example in which the touch panel controller 3 includes the signal processing unit 22 and the inner product calculation unit 23 has been described. However, the present invention is not limited to this. The processing by the signal processing unit 22 and the inner product calculation unit 23 may be executed outside the touch panel controller 3. For example, like the configuration of the mobile phone as the electronic device shown in FIG. 9, the signal AD-converted by the A / D conversion unit 21 of the touch panel controller 3B provided in the touch panel device 1B is sent to the CPU 66 outside the touch panel device 1B. The processing by the signal processing unit 22 and the inner product calculation unit 23 after the A / D conversion unit 21 may be executed by the CPU 66.

  The mobile phone includes a touch panel device 1B and a CPU 66. The touch panel device 1B includes a touch panel 2 and a touch panel controller 3B. The touch panel controller 3B includes a drive unit 10, a drive control unit 11, a differential amplifier OP, and an A / D conversion unit 21. The CPU 66 includes a signal processing unit 22 and an inner product calculation unit 23.

  According to the configuration of the fourth embodiment, the configuration of the touch panel controller 3B itself can be greatly simplified because it is not necessary to provide the signal processing unit 22 and the inner product calculation unit 23 inside the touch panel controller 3B.

[Example 1]
In this example, using the touch panel device 1A according to the first embodiment, an experiment for verifying the effect of correction in the case where parasitic capacitances Cp1 to Cp2 as shown in FIG. Since it went, it demonstrates below.

The condition for the verification is that the capacitances C _{1,1 to} C _2,18 arranged at the positions where the drive line and the sense line intersect each other have a capacitance of 2.2 pF. Further, the integration capacitor Cint of the differential amplifier OP is 8 pF. Furthermore, when there is a touch input, the capacitance values of the capacitances C _{1,1 to} C _2,18 are set to be reduced by 0.2 pF.

In addition, the parasitic capacitance Cp1 of sense line SL ₁ is a 9pF, the parasitic capacitance Cp2 of sense line SL ₂ is set to 11pF.

Further, the driving unit 10, the drive line _{DL 1,} DL 2, ..., the _{DL 18,} each drive line _{DL 1, DL 2, ...,} 18 pieces of sequence length N applied to _{DL 18} (N is N ≧ K Are driven in parallel with a code sequence D _{1 to} D _{K of} an integer satisfying the above. As shown in FIG. 3, code sequences D _{1 to} D _K use code sequences generated by bit-shifting an M sequence (M-sequence) that is a binary pseudorandom number sequence having a sequence length N = 63.

That is, the code sequence D _{1, i to} D _{63, i} changes in value for each clock, becomes the value of the code sequence D _{1,1 to} D _{63,1 in} the first clock, and D _{1,63 in} the 63rd clock. It becomes the value of _-D63,63 . At the 64th clock, the code sequence D _{1,1 to} D _63,1 returns to the same value as the first clock, and the same value is repeated every 63 clocks. The clock signal is 1 MHz. The elements of the code sequences D _{1 to} D _K , that is, the codes D _{1,1 to} D ₁₈ , ₆₃ are either “1” or “−1”.

  Further, the power supply voltage VDD is 3.3V, and the common mode voltage Vcm is 1.65V. The voltage applied to the drive line when the sign is “1” was VDD / 2 + Vcm = 3.3V, and the voltage applied to the drive line when the sign was “−1” was −VDD / 2 + Vcm = 0V.

In a specific parallel driving, in the first 63 clock from the first clock of the first set, in parallel driving the drive line _DL 1 _{through DL 18} with the code sequence _D 1,1 _{~D 18,63.} Next, the driving of the second set is started, and the drive lines DL _{1 to} DL ₁₈ are driven in parallel using the code sequences D _{19,1 to} D _36,63 from the first clock to the 63rd clock of the second set. Next, the third set of parallel driving starts, and the drive lines DL _{1 to} DL ₁₈ are driven in parallel using the code sequences D _{37,1 to} D _54,63 from the first clock to the 63rd clock of the third set. . Next, parallel drive starts in the fourth set, the first 63 clock from the first clock of the fourth set, driven in parallel drive lines _DL 1 through DL ₉ with the code sequence _D 55,1 _{~D 63,63} . It should be noted that the drive line _DL 10 _{~DL 18} is not driven. It is not necessary to drive each set, the second set of the first clock is driven next to the first set of the first clock, then the third set of the first clock and the fourth set of the first clock. May be sequentially driven, and then the first set of second clocks may be driven.

In the parallel drive described above, as shown in FIG. 3, in the first set of drive, the drive lines DL _{1 to} DL ₁₈ are driven by the code sequences D _{1, i to} D _{18, i} , and i = 1 to i The linear sum signal Y1 _i up to = 63 is acquired. In the second set of driving, the drive lines DL _{1 to} DL ₁₈ are driven by D _{19, i to} D _{36, i} to obtain the linear sum signal Y 2 _i from i = 1 to i = 63. In the third set of driving, the drive lines DL _{1 to} DL ₁₈ are driven by the code series D _{37, i to} D _{54, i} to obtain the linear sum signal Y3 _i from i = 1 to i = 63.

In the drive of the fourth set, the drive line _DL 1 through DL ₉ using code sequences _{D 55, i ~D 63, i} , to obtain a linear sum signal Y4 _i from i = 1 to i = 63.

  Thus, if the signals obtained by these driving operations are added, the same effect as N = K = 63 is obtained.

The signal processing unit 22 adds the linear sum signal _{Y1 i ~Y4} i of the outputs a signal Ys _i.

That is, the output signal Ys _i of the signal processing unit 22 is

Given in

  The inner product calculation unit 23 calculates the inner product of the output signal of the signal processing unit 22 and the code sequence as shown in the above equation (8).

Here, an example waveform of the linear sum signal _{Y1 i ~Y4} i when there is a touch input in the vicinity of the intersection of the sense line SL ₁ and the drive line _{DL 11} shown in FIG. 10 (b), the output signal of the signal processing unit 22 A waveform example of Ys _i is shown in FIG. 10A and 10B, the vertical axis represents voltage and the horizontal axis represents time. The signal Y1 _i and the code sequence _{D 1, i} to D _18, the signal at the capacitance value estimated by the inner product operation and the embodiment of the _i Ys _i and the code sequence _{D 1, i ~D 18, i} FIG. 11 shows the capacitance value estimated by the inner product calculation.

  As shown in FIG. 11, when there is a touch input, as described above, the capacitance value changes by 0.2 pF. However, by performing the correction process, it is possible to confirm that the portion with the touch input approaches the original input value of 0.2 pF, while the portion without the touch input approaches the original input value of zero. It was.

[Example 2]
In this example, using the touch panel device 1A of the second embodiment, the effect of the correction was verified by changing the conditions from Example 1.

As a condition for verification in the present embodiment _, in addition to the code sequences D _{1, i to} D _{18, i} , other code sequences are also used for inner product calculation. Specifically, the capacitance value is estimated using the code sequence D _{1, i to} D _{54, i} as shown in the following equation (12).

  The other conditions were the same as in Example 1.

  The result is shown in FIG.

That is, in Example 1 in FIG. 12, when external noise is mixed in the signals Y1 _{i to} Y4 _i , the case where the code series D _{1, i to} D _{18, i} is used for estimation of the capacitance value is shown. In Example 2 in FIG. 12, the estimated value of the electrostatic capacitance when the code series D _{1, i to} D _{54, i} is used is shown.

  In order to see the influence of external noise, comparing the standard deviation of the part without signal, the configuration of Example 1 is 0.0077 pF, and the configuration of Example 2 is 0.0033 pF.

Therefore, by using the code sequences D1 _{, i to} D54 _{, i} for the inner product calculation, the influence of the external noise can be reduced with respect to the variation in the estimated value due to the external noise.

[Summary]
Touch panel controller 3 in embodiment 1 of the present invention, the sense line SL ₁ and K present in the driveline _{(DL 1 ~DL} 18) _(K is a plurality) K-number of the electrostatic capacitance formed between the (C1,1 To C1, 18) are driven in parallel by N K-dimensional vectors included in N Q-dimensional vectors (N is an integer, Q is an integer of 3 or more) representing an M-sequence code, a Gold sequence code, or an orthogonal code. comprises said K capacitance (C1,1~C1,18) driver 10 to output a linear sum signal from the sense line SL ₁ based on charges accumulated in the driving unit 10, the N P of the K capacitances (C1, 1 to C1, 18) are driven in parallel by N P-dimensional vectors (1 ≦ P ≦ K) included in the Q-dimensional vectors, and the P Based on the charge accumulated in each capacitor Another linear sum signal is output from the sense line SL1, and an addition / subtraction signal obtained by adding / subtracting the linear sum signal and the other linear sum signal, and an inner product operation of the N K-dimensional vectors, An inner product calculation unit 23 that estimates values of K electrostatic capacitances (C1, 1 to C1, 18) is further provided.

  According to the above invention, when the touch panel controller touches the touch panel, the touch panel controller is touched by a change in capacitance formed at each intersection of the sense line and the K drive lines on the touch panel. Find the position.

  By the way, in this type of touch panel controller, different parasitic capacitances are attached to each sense line, and an error may occur in the estimated value of each capacitance value due to the influence of the parasitic capacitance.

  Therefore, in the present invention, K electrostatic capacitances formed between the sense line and the K drive lines (K is a plurality) are represented by N Q-dimensional vectors (M-sequence codes or orthogonal codes). N is an integer, Q is an integer of 3 or more) and is driven in parallel to output a linear sum signal based on the charges accumulated in the K capacitances from the sense line. The driving unit drives P of the K capacitances by N P-dimensional vectors (1 ≦ P ≦ K) included in the N Q-dimensional vectors, Another linear sum signal based on the charges accumulated in the P capacitances is output from the sense line. An inner product for estimating the value of the K electrostatic capacitances by an inner product operation of the addition / subtraction signal obtained by adding / subtracting the linear sum signal and the other linear sum signal and the N K-dimensional vectors. An arithmetic unit is further provided.

  As a result, even if the parasitic capacitance existing for each sense line is different, each electrostatic capacitance in which the influence of the parasitic capacitance is reduced by driving the K drive lines in parallel by at least two types of parallel driving methods. An estimate of the value can be obtained.

  Therefore, it is possible to provide a touch panel controller that can correct the influence of the parasitic capacitance existing in the sense line and more accurately estimate the capacitance value.

  The touch panel controller 3 according to the aspect 2 of the present invention is the touch panel controller 3 according to the aspect 1, in which the inner product calculation unit 23 performs the inner product calculation result of the addition / subtraction signal and the N K-dimensional vectors, the addition / subtraction signal, and the N It is preferable to estimate the values of the K capacitances (C1, 1 to C1, 18) based on the result obtained by adding and subtracting the inner product calculation result with the P-dimensional vectors.

  According to the above configuration, in an environment where noise is mixed from the outside, in addition to the inner product calculation result of the addition / subtraction signal and the N K-dimensional vectors, the inner product of the addition / subtraction signal and the N P-dimensional vectors. By using the calculation result, the influence of noise can be reduced. The noise mixed from the outside means thermal noise generated by a circuit, environmental noise mixed in touch input, or the like.

  Therefore, in the case where noise is mixed from the outside, the capacitance value can be estimated more accurately.

  The touch panel controller 3 according to the third aspect of the present invention is the touch panel controller 3 according to the first aspect, wherein the driving unit 10 includes N P-dimensional vectors (P = K, Q = 2K) included in the N Q-dimensional vectors. Preferably, the K capacitances are driven to output another linear sum signal from the sense line SL1 based on the charges accumulated in the K capacitances.

  As described above, since the number K of drive lines is a value determined by the touch panel, in general, the number K of drive lines cannot be controlled. However, the same effect as when the number K of drive lines is increased can be obtained by driving K drive lines a plurality of times and using the sum of the results as a signal.

For example, when N = 63, K = 18, and the code sequence is D _{1 to} D ₆₃ , D _{1 to} D ₁₈ are used in the first drive, and D _{19 to} D ₃₆ are used in the second drive. , D _{37 to} D ₅₄ are used in the third drive, and D _{55 to} D ₆₃ are used in the fourth drive. If the signals obtained by these driving operations are added, the same effect as N = K is obtained.

  In the present invention, for the K drive lines, the first parallel drive method using K sequence length N code sequences and P (P = N−K) sequence length N code sequences are used. By performing at least two types of parallel driving methods with the second parallel driving method, parallel driving with N sequence length N code sequences is performed. As a result, it becomes equivalent to N = K, and the influence of the parasitic capacitance represented by “a * (N−K + 1)” can be set to the minimum value “a”.

  The integrated circuit according to aspect 4 of the present invention preferably includes the touch panel controller 3 according to any one of aspects 1 to 3.

  Thereby, the integrated circuit which integrated the touch panel controller which can estimate an electrostatic capacitance value more correctly can be provided.

  The electronic device (mobile phone 60) according to the fifth aspect of the present invention preferably includes the touch panel controller 3 according to any one of the first to third aspects and the touch panel 2 controlled by the touch panel controller 3.

  Thereby, the electronic device provided with the touch panel controller which can estimate an electrostatic capacitance value more correctly can be provided.

  In the electronic device according to the sixth aspect of the present invention, the K capacitances formed between the sense line and the K drive lines (K is a plurality) represent an M series code, a Gold series code, or an orthogonal code. Driven in parallel by N K-dimensional vectors included in N Q-dimensional vectors (N is an integer, Q is an integer of 3 or more), and a linear sum signal based on charges accumulated in the K electrostatic capacitances is obtained. The driving unit 10 is configured to output from the sense line, and the driving unit 10 has the K electrostatic capacitances by N P-dimensional vectors (1 ≦ P ≦ K) included in the N Q-dimensional vectors. Touch panel controller 3B that drives P of them in parallel and outputs another linear sum signal based on the charges accumulated in the P capacitors from the sense line, and is controlled by the touch panel controller 3B. An electronic apparatus including a touch panel 2 and a central processing unit (CPU 66) that receives the linear sum signal and the other linear sum signal, wherein the central processing unit (CPU 66) An inner product calculation unit 23 that estimates the value of the K electrostatic capacitances by an inner product calculation of an addition / subtraction signal obtained by adding / subtracting the other linear sum signal and the N K-dimensional vectors. Features.

  Thereby, it is possible to provide an electronic device that can more accurately estimate the capacitance value while simplifying the configuration of the touch panel controller.

  The touch panel device 1 or 1A according to aspect 7 of the present invention is the touch panel device 1 or 1A including the touch panel controller 3 according to any one of aspects 1 to 3, and is a touch panel controlled by the touch panel controller 3. 2 is provided.

  An integrated circuit according to aspect 8 of the present invention is characterized in that the touch panel controller 3 according to any one of aspects 1 to 3 is integrated.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the technical means disclosed in different embodiments can be appropriately combined. Such embodiments are also included in the technical scope of the present invention.

  INDUSTRIAL APPLICABILITY The present invention can be used for a touch panel controller that drives or drives a plurality of drive lines in parallel to estimate or detect a capacitance value of a capacitance configured in a matrix, and an electronic device using the touch panel controller. The present invention can also be applied to a fingerprint detection system.

1.1A Touch Panel Device 2 Touch Panel 3 Touch Panel Controller 4 Stylus Pen 10 Drive Unit 11 Drive Control Unit (Drive Unit)
21 AD converter 22 Signal processor 23 Inner product calculator 60 Mobile phone (electronic equipment)
61 Display panel 66 CPU (Central processing unit)
C1,1~CL, K capacitance _C 1,1 _{~C L, K} capacitance value Cp1, Cp2 parasitic capacitance _D 1 to D _K code sequence _DL 1 _{through DL 18} driveline OP differential amplifier SL1, SL2 sense Line X1, X2 input signal Y1, Y2 output signal

Claims (5)

N capacitances formed between a sense line and K drive lines (K is a plurality) are represented by N Q-dimensional vectors (N is an integer) representing an M-sequence code, a Gold-sequence code, or an orthogonal code. , Q is an integer greater than or equal to 3) and is driven in parallel by N K-dimensional vectors, and includes a drive unit that outputs a linear sum signal based on the charges accumulated in the K capacitances from the sense line. ,
The driving unit drives P of the K capacitances in parallel by N P-dimensional vectors (1 ≦ P ≦ K) included in the N Q-dimensional vectors, Another linear sum signal based on the charge accumulated in the capacitance is output from the sense line;
An inner product operation unit that estimates the value of the K capacitances by an inner product operation of an addition / subtraction signal obtained by adding / subtracting the linear sum signal and the other linear sum signal and the N K-dimensional vectors. A touch panel controller, further comprising:   The inner product operation unit adds a result obtained by adding / subtracting an inner product operation result of the addition / subtraction signal and the N K-dimensional vectors and an inner product operation result of the addition / subtraction signal and the N P-dimensional vectors to the result The touch panel controller according to claim 1, wherein the K capacitance values are estimated based on the K capacitance values.   The driving unit drives the K electrostatic capacitances by N P-dimensional vectors (P = K, Q = 2K) included in the N Q-dimensional vectors, and the K electrostatic capacitances are driven. The touch panel controller according to claim 1, wherein another linear sum signal based on the accumulated charge is output from the sense line. The touch panel controller according to any one of claims 1 to 3,
An electronic apparatus comprising: a touch panel controlled by the touch panel controller. N capacitances formed between a sense line and K drive lines (K is a plurality) are represented by N Q-dimensional vectors (N is an integer) representing an M-sequence code, a Gold-sequence code, or an orthogonal code. , Q is an integer greater than or equal to 3) and is driven in parallel by N K-dimensional vectors, and includes a drive unit that outputs a linear sum signal based on the charges accumulated in the K capacitances from the sense line. The driving unit drives P of the K capacitors in parallel by N P-dimensional vectors (1 ≦ P ≦ K) included in the N Q-dimensional vectors, A touch panel controller that outputs another linear sum signal based on the electric charge accumulated in the capacitance of the sense line;
A touch panel controlled by the touch panel controller;
An electronic device comprising a central processing unit that receives the linear sum signal and the other linear sum signal,
The central processing unit performs an inner product operation of an addition / subtraction signal obtained by adding / subtracting the linear sum signal and the other linear sum signal and the N K-dimensional vectors to calculate the K capacitances. An electronic device comprising an inner product calculation unit for estimating a value.

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