JP2013097687A - Touch panel driving device, touch panel driving method, display device, program, and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a touch panel driving device that can prevent false detection of a touch position and has good operability.SOLUTION: A touch panel controller 40 comprises: a touch panel driving unit 41; an input operation detection unit 42; a noise reduction unit 44 for reducing the influence of noise generated from a liquid crystal panel 11; a noise amount estimation unit 43 for estimating the amount of the noise from a display image; and a reduction level control unit 45 for controlling the level of noise reduction processing depending on the amount of the noise.

Description

  The present invention relates to a touch panel driving device that drives a touch panel.

  In a display device including a touch panel as an input device, there is a problem that the touch panel malfunctions due to noise caused by display operation of the display device. For example, in a liquid crystal display device equipped with a touch panel, the polarity of a drive signal acting on the liquid crystal is usually inverted every frame period or every line scanning period as a countermeasure against flicker or image sticking. In this case, the polarity of the common voltage set to a constant voltage value is often reversed every cycle. Noise is generated at the timing of reversing the polarity of the common voltage. When this noise is superimposed on the drive voltage of the touch panel, the touch panel sensitivity is deteriorated and the touch position is erroneously detected.

  Therefore, in the conventional display device, a measure for providing a noise filter for reducing noise due to the display operation is taken. However, the amount of noise due to the display operation varies depending on the displayed image and the driving method of the display device. Therefore, the noise reduction amount by the noise filter needs to correspond to the assumed maximum noise amount.

  Generally, the response speed of the touch panel becomes longer as the amount of noise reduction by the noise filter increases. Therefore, when the noise reduction amount by the noise filter is made to correspond to the assumed maximum noise amount, the response speed of the touch panel is always increased, and the operability is deteriorated.

  On the other hand, Patent Document 1 discloses a technique for generating a mask signal voltage in correspondence with the polarity inversion timing of the common voltage and temporarily stopping the touch panel drive in synchronization with the mask signal voltage. . As a result, the touch position can be accurately detected without being affected by noise due to polarity inversion of the common voltage.

JP2011-1000018 (published on May 19, 2011)

  However, in the technique described in Patent Document 1, since the touch panel is driven in accordance with the polarity inversion timing of the common voltage, the coordinate update rate is restricted to liquid crystal driving. Since the driving frequency of a normal liquid crystal display device is 60 Hz, the coordinate update rate cannot exceed 60 Hz. Therefore, there is a problem that the technique described in Patent Document 1 cannot be applied to applications that require a fast coordinate update rate such as pen input.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to realize a touch panel drive device and a touch panel drive method that can prevent erroneous detection of the touch position and have good operability. is there.

  In order to solve the above problems, a touch panel drive device according to the present invention includes a drive unit that drives a touch panel used in a display device, and a detection unit that detects an input operation on the touch panel based on an output signal of the touch panel. And a noise reduction means for reducing the influence of noise generated from the display screen of the display device on the detection means, wherein the amount of the noise is estimated from an image displayed on the display screen And a reduction level control means for controlling the level of noise reduction processing by the noise reduction means in accordance with the amount of noise estimated by the noise quantity estimation means.

  In order to solve the above problems, a touch panel driving method according to the present invention is a touch panel driving method used in a display device, and detects detection of an input operation to the touch panel based on an output signal of the touch panel. A noise reduction step for reducing the influence of noise generated from the display device on the detection, a noise amount estimation step for estimating the amount of noise from an image displayed on the display device, and the noise amount estimation And a reduction level control step for controlling the level of noise reduction processing in the noise reduction step according to the amount of noise estimated in the step.

  In general, in the process of reducing noise generated from the display screen of the display device, the operability of the touch panel decreases, such as the detection sensitivity of the input operation decreases and the power consumption increases as the amount of noise reduction increases. On the other hand, according to the above configuration, the level of the noise reduction process is controlled according to the amount of noise estimated from the image displayed on the display device. That is, the greater the estimated amount of noise, the greater the amount of noise reduction, and the smaller the estimated amount of noise, the smaller the amount of noise reduction. Therefore, by making the amount of noise reduction necessary and sufficient to prevent malfunctions, the operability is improved compared to a configuration in which the level of noise reduction processing is made constant corresponding to the maximum amount of noise assumed. Can do. Therefore, erroneous detection of the touch position can be prevented, and a touch panel driving device and a touch panel driving method with good operability can be realized.

  In the touch panel drive device according to the present invention, the noise reduction unit is configured by a noise filter that filters noise included in the output signal of the touch panel, and the reduction level control unit changes a filter coefficient of the noise filter. Therefore, it is preferable to control the level of noise reduction processing by the noise reduction means.

  According to the above configuration, by setting the filter constant of the noise filter to a necessary and sufficient value for preventing malfunction according to the estimated amount of noise, the input operation can be performed compared to the configuration in which the filter constant is constant. Detection sensitivity can be improved.

  In the touch panel drive device according to the present invention, the noise reduction means reduces the influence by increasing a drive voltage for the drive means to drive the touch panel, and the reduction level control means includes the drive It is preferable to control the level of noise reduction processing by the noise reduction means by changing the voltage.

  The higher the drive voltage for driving the touch panel, the higher the SN ratio, so the influence of noise can be reduced. Therefore, by setting the driving voltage for driving the touch panel to a value necessary and sufficient for preventing malfunction according to the estimated amount of noise, the power consumption can be reduced compared to the configuration in which the driving voltage for the touch panel is constant. Can be suppressed.

  In the touch panel drive device according to the present invention, the noise reduction unit reduces the influence by lengthening a drive cycle of the touch panel by the drive unit, and the reduction level control unit changes the drive cycle. It is preferable to control the level of noise reduction processing by the noise reduction means.

  The longer the touch panel drive cycle, the longer the scan time, so the influence of noise can be reduced. Therefore, the detection sensitivity of input operations is improved by setting the touch panel drive cycle to a value that is necessary and sufficient to prevent malfunctions according to the estimated amount of noise, compared to a configuration in which the touch panel drive cycle is constant. Can be made.

  In the touch panel drive device according to the present invention, the noise amount estimating unit estimates the amount of noise for each of a plurality of display areas of the display screen, and the noise reducing unit is configured such that the noise amount estimating unit includes the plurality of displays. It is preferable to control the level of noise reduction processing by the noise reduction unit for each area of the touch panel corresponding to the plurality of display areas in accordance with the amount of noise estimated for each area.

  According to the above configuration, since the level of the noise reduction process is controlled for each of the plurality of regions of the touch panel, the level of the noise reduction process can be further finely controlled.

  In the touch panel drive device according to the present invention, each of the plurality of regions corresponds to a detection unit region of the touch panel, and the noise reduction unit estimates the noise amount estimation unit for each of the plurality of display regions. It is preferable to control the level of noise reduction processing by the noise reduction unit for each detection unit region in accordance with the amount of noise.

  According to the above configuration, since the level of the noise reduction process is controlled for each detection unit area of the touch panel, the level of the noise reduction process can be minimized.

  A display device according to the present invention is a display device that includes a touch panel and a touch panel drive device that drives the touch panel, and includes the touch panel drive device described above as the touch panel drive device.

  The display device according to the present invention may be a liquid crystal display device.

  The touch panel drive device may be realized by a computer. In this case, a program that causes the computer to operate as each unit of the touch panel drive device and a computer-readable recording medium that records the program are also included in the present invention. Included in the technical scope.

  As described above, the touch panel drive device according to the present invention includes a drive unit that drives a touch panel used in a display device, a detection unit that detects an input operation on the touch panel based on an output signal of the touch panel, and the display A noise reduction unit for estimating the amount of noise from an image displayed on the display device, comprising: a noise reduction unit that reduces an influence of noise generated from a display screen of the device on the detection unit And a reduction level control means for controlling the level of noise reduction processing by the noise reduction means according to the amount of noise estimated by the noise amount estimation means.

  The touch panel drive method according to the present invention is a touch panel drive method used for a display device, and includes a detection step of detecting an input operation on the touch panel based on an output signal of the touch panel, and the display device. A noise reduction step for reducing the influence of generated noise on the detection; a noise amount estimation step for estimating the amount of noise from an image displayed on the display device; and the noise estimated in the noise amount estimation step And a reduction level control step for controlling the level of noise reduction processing in the noise reduction step according to the amount of noise.

  Accordingly, it is possible to prevent erroneous detection of the touch position and to realize a touch panel drive device and a touch panel drive method with good operability.

It is a block diagram which shows the structure of the liquid crystal display device which concerns on embodiment of this invention. It is a figure which shows the specific structure of the touchscreen of the said liquid crystal display device. It is a block diagram which shows the structure of the touchscreen controller of the said liquid crystal display device. It is a figure which shows the structure of the noise reduction part of the said liquid crystal display device, and a reduction level control part. It is a figure for demonstrating the estimation method of noise amount. It is a figure which shows the state which is controlling the level of the noise reduction process for every area | region corresponding to the drive line of a touch panel. It is a figure which shows the state which is controlling the level of the noise reduction process for every detection unit area | region of a touch panel.

  An embodiment of the present invention will be described below with reference to FIGS.

(Configuration of liquid crystal display device)
FIG. 1 is a block diagram showing a configuration of a liquid crystal display device 1 according to the present embodiment. The liquid crystal display device 1 includes a liquid crystal module 10, a liquid crystal controller 20, a touch panel 30, a touch panel controller 40, and a host controller 50.

  The liquid crystal module 10 includes a liquid crystal panel 11 and a liquid crystal driver 12.

  The liquid crystal panel 11 is provided with gate lines, source lines, and display pixels. A plurality of gate lines are provided in parallel with each other at a predetermined interval. On the other hand, a plurality of source lines are provided in parallel to each other at a predetermined interval in a direction orthogonal to the gate lines. The display pixel is provided at each intersection of the gate line and the source line. Each display pixel is connected with a TFT as a switching element.

  The liquid crystal driver 12 includes a gate driver that drives the gate line and a source driver that drives the source line. The gate driver sequentially outputs a scanning signal for turning on the TFT to each gate line. The source driver outputs a gradation display voltage (drive voltage) to each source line.

  When the TFT is in an on state, a drive voltage from the gate line is applied to the display pixel, and charges are accumulated. Thereby, the light transmittance of the liquid crystal changes according to the drive voltage, and the image display on the liquid crystal panel 11 is performed.

  In order to prevent flicker and image sticking, the liquid crystal panel 11 is AC driven, and the polarity of the drive voltage applied to the display pixel is 1 or more for each gate line, 1 or more for each source line and 1 or Inversion is performed for each of a plurality of frames (dot inversion driving method). In addition, there is a method of inverting every one or a plurality of source lines and every one or a plurality of frames (line inversion method).

  Based on the display data D supplied from the host controller 50, the liquid crystal controller 20 sends the display data D to the liquid crystal driver 12 together with signals for controlling the display of the liquid crystal panel 11, such as a vertical synchronization signal VS2 and a horizontal synchronization signal HS. Supply. Thereby, the drive timing of the liquid crystal display is controlled, and an image of the display data D is displayed on the liquid crystal panel 11.

  Further, the liquid crystal controller 20 is configured to supply the display data D to the touch panel controller 40 as well. As will be described later, the touch panel controller 40 estimates the amount of noise generated from the liquid crystal panel 11 based on the display data D.

  The touch panel 30 is an input device provided for performing a touch operation on the display screen of the liquid crystal panel 11. When a touch operation is performed on the touch panel 30, the touch panel 30 outputs a signal corresponding to the touch position.

(Configuration of touch panel)
Although any type of touch panel can be used as the touch panel 30, a capacitive touch panel is used in the present embodiment.

  FIG. 2 is a diagram illustrating a specific configuration of the touch panel 30. The touch panel 30 includes x drive lines T1 to Tx, y sense lines R1 to Ry, and capacitances C11 to Cxy. The drive lines T1 to Tx and the sense lines R1 to Ry are arranged in a lattice shape, and the capacitances C11 to Cxy are formed at the intersections of the drive lines T1 to Tx and the sense lines R1 to Ry.

  The drive lines T1 to Tx and the sense lines R1 to Ry are connected to the touch panel controller 40. The touch panel controller 40 corresponds to the touch panel drive device described in the claims. As shown in FIG. 1, the touch panel drive unit 41, the input operation detection unit 42, the noise amount estimation unit 43, and the noise reduction unit 44. And a reduction level control unit 45.

  The touch panel drive unit 41 corresponds to drive means described in the claims, and sequentially applies voltage signals to the drive lines T1 to Tx of the touch panel 30. Thereby, electric charges are stored in the capacitances C11 to Cxy. Here, when an object touches the touch panel 30, the capacitance value of the capacitance corresponding to the contact position changes, and the current value of the sense line to which the capacitance is connected changes. The input operation detection unit 42 of the touch panel controller 40 can detect a touch position, a touch range, and the like based on output signals of the sense lines R1 to Ry. The input operation detection unit 42 corresponds to detection means described in the claims.

(Overview of noise reduction)
The noise amount estimation unit 43, the noise reduction unit 44, and the reduction level control unit 45 correspond to the noise amount estimation unit, the noise reduction unit, and the reduction level control unit described in the claims, respectively.

  The noise amount estimation unit 43 has a function of estimating the amount of noise generated from the liquid crystal panel 11 based on the display data D input from the liquid crystal controller 20. The amount of noise generated from the liquid crystal panel 11 varies depending on the content of the image displayed on the liquid crystal panel 11. For example, in the case of the dot inversion driving method, the amount of noise increases as the luminance difference from adjacent pixels or the amplitude of the driving voltage increases. Specific contents regarding the estimation of the noise amount will be described later.

  The noise reduction unit 44 has a function of reducing the influence of noise generated from the liquid crystal panel 11 on the input operation detection unit 42, and is configured by, for example, a noise filter that filters noise.

  The reduction level control unit 45 has a function of controlling the level of noise reduction processing by the noise reduction unit 44 in accordance with the amount of noise estimated by the noise amount estimation unit 43. More specifically, as the amount of noise estimated by the noise amount estimation unit 43 increases, the reduction level control unit 45 increases the level of noise reduction processing by the noise reduction unit 44, that is, the amount of noise increases. Control to be reduced.

  Thereby, when it is estimated that the amount of noise generated from the liquid crystal panel 11 is relatively large, the amount of noise reduction by the noise reduction unit 44 increases, and when the amount of noise is estimated to be relatively small, The amount of noise reduction by the noise reduction unit 44 is reduced.

  Here, when the noise reduction part 44 is comprised by a noise filter, the detection time of the input operation detection part 42 becomes long, so that the amount of noise reduction increases (response speed becomes slow). However, in a configuration in which the level of noise reduction processing is constant, in order to prevent malfunction, it is necessary to make the level correspond to the maximum amount of noise assumed, and as a result, the detection time of the input operation is always long. End up.

  On the other hand, in the present embodiment, the noise reduction processing can be set to a necessary and sufficient level according to the estimated amount of noise, so that the input as a whole is compared with a configuration in which the noise reduction processing level is constant. The operation detection time can be shortened.

(Configuration example of touch panel controller)
Next, a more specific configuration of the touch panel controller 40 will be described with reference to FIGS. 3 and 4.

  FIG. 3 is a block diagram illustrating a configuration of the touch panel controller 40. The touch panel drive unit 41 of the touch panel controller 40 is connected to the drive lines T1 to Tx of the touch panel 30 and sequentially drives the drive lines T1 to Tx.

  The input operation detection unit 42 includes a sampling unit 42a and a touch position calculation unit 42b. The sampling unit 42 a is connected to the sense lines R 1 to Ry of the touch panel 30, samples the output signals of the sense lines R 1 to Ry sequentially, and inputs the sampled data to the noise reduction unit 44.

  FIG. 4 is a diagram illustrating the configuration of the noise reduction unit 44 and the reduction level control unit 45. The noise reduction unit 44 is configured by an IIR filter (infinite impulse response filter), and includes a multiplier 44a, an adder 44b, a register 44c, and a multiplier 44d having a coefficient 1-A, with a coefficient A (0 <A <1). I have. Data from the sampling unit 42a is input to the adder 44b via the multiplier 44a. The register 44c and the multiplier 44d form a feedback path for handling the data from the sampling unit 42a with an infinite length. The register 44c functions as a delay circuit for one frame period.

Here, when the noise amount estimated by the noise amount estimation unit 43 at the i-th frame is Z _i and the initial value of the filter coefficient of the IIR filter is B (usually 0)

It becomes. Therefore, if the data (voltage measurement value) measured at the i-th frame input from the sampling unit 42a is P _i , the integrated value SP _u of the voltage at the u-th frame used by the touch position calculation unit 42b for touch presence / absence determination. Is

It becomes.

  Further, the reduction level control unit 45 can control the filter coefficients of the IIR filter by controlling the coefficients of the multipliers 44a and 44d. As A is closer to 1, the amount of noise reduction increases, but the touch detection time becomes longer. On the other hand, as A approaches 0, the noise reduction amount decreases, but the touch detection time becomes shorter.

(Noise estimation method)
Next, a noise amount estimation method by the noise amount estimation unit 43 will be described. In the present embodiment, an estimation method using a histogram is used. As described above, the noise amount estimation unit 43 estimates the amount of noise generated by the liquid crystal panel 11 based on the display data D input from the liquid crystal controller 20.

  FIG. 5A is a diagram showing a display image of the liquid crystal panel 11 in the first frame, and FIG. 5B is an enlarged view of a part of the display image. Further, FIG. 5C is a diagram showing the luminance of the pixels in the range of the gate lines G1 to G2 and the source lines S1 to S5 corresponding to a part of the display image shown in FIG.

  Since the liquid crystal panel 11 is driven by the dot inversion driving method, the polarity of the drive signal is inverted for each gate line and each source line. Therefore, as shown in FIG. 5D, the polarities of adjacent sub-pixels are different from each other.

  Here, it is known that more noise is generated as the potential difference (gradation difference, luminance difference) between adjacent sub-pixels is higher. Therefore, as shown in FIG. 5E, in the pixel located at the intersection of the gate line G1 and the source line S1, or the pixel located at the intersection of the gate line G1 and the source line S3, the potential difference between adjacent sub-pixels. Therefore, it is estimated that the amount of noise is large. On the other hand, for example, in the pixel located at the intersection of the gate line G2 and the source line S1, the driving voltage of the two subpixels is low, so that the potential difference between adjacent subpixels is small and the amount of noise is estimated to be small. Furthermore, for example, in the pixel located at the intersection of the gate line G1 and the source line S2, it is estimated that the amount of noise is very small because the drive voltage of all the sub-pixels is low. In this way, the amount of noise can be estimated for each pixel.

  FIG. 5F is a diagram illustrating the estimated noise amount of each pixel. The total noise amount of each pixel is the amount of noise generated by the liquid crystal panel 11 per frame. Thus, the noise amount estimation unit 43 can estimate the amount of noise generated by the liquid crystal panel 11 based on the potential difference between adjacent subpixels.

(Summary)
As described above, in accordance with the amount of noise estimated by the noise amount estimation unit 43, the reduction level control unit 45 changes the filter coefficient of the noise reduction unit 44 configured by the IIR filter to perform noise reduction processing. Control the level. As a result, when the amount of noise is large, the touch detection time becomes long, but the noise resistance becomes high, so that malfunction can be prevented. In addition, when the amount of noise is small, noise resistance can be reduced, so that the touch detection time can be shortened.

  Therefore, compared to a configuration in which the level of noise reduction processing is constant, the level of noise reduction processing can be set to a level that is necessary and sufficient to prevent malfunctions, so the detection time of input operations as a whole can be shortened. And operability can be improved.

(Example by software)
Each block of the touch panel controller 40, in particular, the touch panel drive unit 41, the input operation detection unit 42, the noise amount estimation unit 43, the noise reduction unit 44, and the reduction level control unit 45 is a logic circuit formed on an integrated circuit (IC chip). May be realized in hardware, or may be realized in software using a CPU (Central Processing Unit).

  In the latter case, the touch panel controller 40 includes a CPU that executes instructions of a program that realizes each function, a ROM (Read Only Memory) that stores the program, a RAM (Random Access Memory) that expands the program, the program, and various programs. A storage device (recording medium) such as a memory for storing data is provided. An object of the present invention is to provide a recording medium in which a program code (execution format program, intermediate code program, source program) of a control program for the touch panel controller 40, which is software that realizes the functions described above, is recorded so as to be readable by a computer. This can also be achieved by supplying to the touch panel controller 40 and reading and executing the program code recorded on the recording medium by the computer (or CPU or MPU).

  Examples of the recording medium include tapes such as magnetic tapes and cassette tapes, magnetic disks such as floppy (registered trademark) disks / hard disks, and disks including optical disks such as CD-ROM / MO / MD / DVD / CD-R. IC cards (including memory cards) / optical cards, semiconductor memories such as mask ROM / EPROM / EEPROM / flash ROM, PLD (Programmable logic device), FPGA (Field Programmable Gate Array), etc. Logic circuits can be used.

  Further, the liquid crystal display device 1 including the touch panel controller 40 may be configured to be connectable to a communication network, and the program code may be supplied via the communication network. The communication network is not particularly limited as long as it can transmit the program code. For example, the Internet, intranet, extranet, LAN, ISDN, VAN, CATV communication network, virtual private network, telephone line network, mobile communication network, satellite communication network, and the like can be used. The transmission medium constituting the communication network may be any medium that can transmit the program code, and is not limited to a specific configuration or type. For example, even with wired lines such as IEEE 1394, USB, power line carrier, cable TV line, telephone line, and ADSL (Asymmetric Digital Subscriber Line) line, infrared rays such as IrDA and remote control, Bluetooth (registered trademark), IEEE 802.11 wireless, HDR ( It can also be used by wireless such as High Data Rate (NFC), Near Field Communication (NFC), Digital Living Network Alliance (DLNA), mobile phone network, satellite line, and digital terrestrial network. The present invention can also be realized in the form of a computer data signal embedded in a carrier wave in which the program code is embodied by electronic transmission.

(Summary of embodiment)
In the above-described embodiment, the noise reduction unit 44 is configured by an IIR filter. However, for example, a noise filter such as an FIR filter (finite impulse response filter) or an adaptive filter (adaptive filter) can be used.

  Further, the reduction level control unit 45 controls the level of the noise reduction process by changing the filter coefficient of the noise filter, but the configuration for controlling the level of the noise reduction process is not limited to this. For example, the level of the noise reduction process may be controlled by changing the drive voltage applied by the touch panel drive unit 41 to the drive lines T1 to Tx of the touch panel 30. In this case, the higher the drive voltage, the higher the S / N ratio, so the level of noise reduction processing increases (noise is reduced more).

  Alternatively, the level of the noise reduction process may be controlled by changing the driving cycle (one scan time) of the touch panel 30. In this case, the longer the drive cycle, the higher the level of noise reduction processing.

  In the above-described embodiment, the noise amount estimation unit 43 estimates the total amount of noise generated by each pixel of the liquid crystal panel 11, and the reduction level control unit 45 determines the sum of the estimated noise amounts. The level of noise reduction processing by the noise reduction unit 44 is controlled. In contrast, the liquid crystal panel 11 is divided into a plurality of regions, the noise amount estimation unit 43 estimates the noise amount for each of the plurality of display regions, and the reduction level control unit 45 corresponds to the plurality of display regions. The level of the noise reduction process may be controlled for each area of the touch panel 30 to be performed.

  For example, as shown in FIG. 6, the touch panel 30 is divided into regions corresponding to the drive lines T1 to Tx, and the drive voltages of the drive lines T1 to Tx are made different to reduce noise for each region of the touch panel 30. The level of processing can be controlled.

  Further, the reduction level control unit 45 may control the level of the noise reduction processing for each detection unit area of the touch panel 30 (area corresponding to each capacitance when the touch panel 30 is a capacitive touch panel). Good.

  For example, as shown in FIG. 7, the level of the noise reduction process can be controlled for each area of the touch panel 30 by changing the filter coefficient of the filtering process corresponding to the area for each detection unit area of the touch panel 30. it can. As a result, the level of noise reduction processing can be minimized, and operability can be further improved.

  In the above-described embodiment, the noise amount estimation method using the histogram when the liquid crystal panel 11 is driven by the dot inversion drive method has been described. However, the noise amount estimation method is not limited to this. For example, an estimation method based on pattern matching or an estimation method based on FFT (Fast Fourier Transform) can be used. Further, according to the driving method (dot inversion driving method, line inversion driving method, etc.) of the liquid crystal panel 11 and the type of display device (liquid crystal display device, organic EL display device, etc.), the noise amount estimation method is a well-known method. It is selected appropriately.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention.

  The touch panel drive device according to the present invention can be used not only for a liquid crystal display device but also for any display device such as an organic EL display device.

DESCRIPTION OF SYMBOLS 1 Liquid crystal display device 10 Liquid crystal module 11 Liquid crystal panel 12 Liquid crystal driver 20 Liquid crystal controller 30 Touch panel 40 Touch panel controller (touch panel drive device)
41 Touch panel drive unit (touch panel drive means)
42 Input operation detection unit (detection means)
42a Sampling unit 42b Touch position calculation unit 43 Noise amount estimation unit (noise amount estimation means)
44 Noise reduction part (noise reduction means)
44a multiplier 44b adder 44c register 44d multiplier 45 reduction level control unit (reduction level control means)
50 Host Controller C11-Cxy Capacitance R1-Ry Sense Line T1-Tx Drive Line

Claims (11)

Driving means for driving a touch panel used in the display device;
Detecting means for detecting an input operation to the touch panel based on an output signal of the touch panel;
A noise reduction means for reducing the influence of noise generated from the display screen of the display device on the detection means,
Noise amount estimating means for estimating the amount of noise from an image displayed on the display screen;
A touch panel drive device comprising: a reduction level control unit that controls a level of noise reduction processing by the noise reduction unit according to the amount of noise estimated by the noise amount estimation unit. The noise reduction means is composed of a noise filter that filters noise included in the output signal of the touch panel,
The touch panel drive device according to claim 1, wherein the reduction level control unit controls a level of noise reduction processing by the noise reduction unit by changing a filter coefficient of the noise filter. The noise reducing means reduces the influence by increasing a driving voltage for the driving means to drive the touch panel.
The touch panel drive device according to claim 1, wherein the reduction level control unit controls a level of noise reduction processing by the noise reduction unit by changing the drive voltage. The noise reduction means reduces the influence by extending the driving period of the touch panel by the driving means,
The touch panel drive device according to claim 1, wherein the reduction level control unit controls a level of noise reduction processing by the noise reduction unit by changing the drive cycle. The noise amount estimating means estimates the amount of noise for each of a plurality of display areas of the display screen,
The noise reduction means is configured to reduce noise by the noise reduction means for each area of the touch panel corresponding to the plurality of display areas according to the amount of noise estimated by the noise amount estimation means for each of the plurality of display areas. The touch panel drive device according to any one of claims 1 to 4, wherein a level of processing is controlled. Each of the plurality of areas corresponds to a detection unit area of the touch panel,
The noise reduction means controls the level of noise reduction processing by the noise reduction means for each detection unit area according to the amount of noise estimated by the noise amount estimation means for each of the plurality of display areas. The touch panel drive device according to claim 5, wherein A display device comprising a touch panel and a touch panel drive device that drives the touch panel,
A display device comprising the touch panel drive device according to claim 1 as the touch panel drive device.   The display device according to claim 7, wherein the display device is a liquid crystal display device. A method of driving a touch panel used in a display device,
A detection step of detecting an input operation to the touch panel based on an output signal of the touch panel;
A noise reduction step for reducing the influence of noise generated from the display device on the detection;
A noise amount estimating step of estimating the amount of noise from an image displayed on the display device;
A touch panel driving method comprising: a reduction level control step for controlling a level of noise reduction processing in the noise reduction step according to the amount of noise estimated in the noise amount estimation step.   The program for operating a computer as each means of the touchscreen drive device of any one of Claims 1-6.   The computer-readable recording medium which recorded the program of Claim 10.

Images