KR20140044688A - Apparatus and method for driving touch sensor - Google Patents

Abstract

The present invention relates to a device and a method for driving a touch sensor. The present invention comprises a touch sensor; a read-out circuit which drives the touch sensor and detects and outputs low data by touch node using a read-out signal by channel received from the touch sensor; a signal processor which determines touch by comparing the low data provided from the read-out circuit and a preset reference value, calculates and outputs a touch coordinate according to the determined result, and a reset the reference value whenever the power is turned on. The signal processor collects the low data by touch node during multiple frames and reset the reference value by using the low data included in a reference range among the collected low data. [Reference numerals] (AA) Start(power on); (BB) No; (CC) Yes; (DD) End; (S10) Collect low data; (S20) Part of the low data is in a first reference range?; (S30) Normal distribution of the low data in the first reference range; (S40) Set a second reference range; (S50) Set a base line; (S60) Set a reference value

Description

TECHNICAL FIELD [0001] The present invention relates to an apparatus and a method for driving a touch sensor,

The present invention relates to an apparatus and method for driving a touch sensor.

The touch sensor driving device senses a touch and a touch position generated by the touch sensor on the display device and outputs touch information, and the computer system analyzes the touch information and performs an instruction. As a display device, a flat panel display device such as a liquid crystal display device, a plasma display panel, and an organic light emitting diode display device is mainly used. As the touch sensor technology, there are resistance film type, capacitive type, optical type, infrared type, ultrasonic type, and electromagnetic type depending on the sensing principle.

The touch sensor may be constituted by an on-cell touch sensor or an add-on touch sensor which is manufactured in the form of a panel and attached to the upper part of the display device, And an in-cell touch sensor (built-in). As a touch sensor, a photo-touch sensor that recognizes a touch according to light intensity using a phototransistor and a capacitive touch sensor that recognizes a touch according to a capacitive variable are mainly used.

Generally, in a touch sensor driving apparatus, a lead-out IC (Integrated Circuit) drives a touch sensor and detects row data using a read-out signal received from a touch sensor. A micro control unit (MCU), which is a signal processor, compares raw data with a reference value to determine whether or not there is touch, calculates touch coordinates, and transmits the touch coordinates to the host computer. The host computer executes commands corresponding to the touch coordinates.

The conventional MCU compares the row data for each touch node with a preset reference value to determine whether or not the touch is made. Accordingly, when the low data varies according to the noise of the surrounding environment, there is a case where the touch is not sensed Thereby deteriorating the touch sensing sensitivity and accuracy.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an apparatus and method for driving a touch sensor capable of improving touch sensitivity and accuracy by adaptively resetting a reference value and applying the reference value to the determination of presence or absence of touch have.

According to an aspect of the present invention, there is provided an apparatus for driving a touch sensor including: a touch sensor; A readout circuit for driving the touch sensor and detecting and outputting row data for each touch node using a readout signal for each channel received from the touch sensor; A signal processor for comparing the row data provided from the lead-out circuit with a preset reference value to determine whether or not a touch is present, calculating and outputting touch coordinates according to the touch presence / absence determination result, and resetting the reference value each time the power is turned on and; Wherein the signal processor collects the row data for each touch node during a plurality of frames and resets the reference value using raw data included in a reference range of the collected row data.

Wherein the signal processor comprises: a touch determination unit for determining whether the touch is present and resetting the reference value; A touch coordinates calculation unit for calculating the touch coordinates; And an interface unit for relaying the touch coordinate output.

The touch determiner collects the touch data for each touch node during a plurality of frames, normalizes the row data included in the first reference range among the collected row data, And the reference value is reset by using the set base value.

And the first reference range is set to a range that the row data can have in the absence of a touch.

And the second reference range is set to m ± nσ (n is a natural number) when the average of the normally distributed row data is m and the standard deviation is σ.

The touch determiner collects the row data for each touch node during a plurality of frames in the absence of a touch, normalizes the collected row data, and selects one of the row data included in the reference range among the normally- And the reference range is m ± nσ (n is a natural number) when the average of the normally distributed raw data is m and the standard deviation is σ, Is a natural number).

The base value is set to one of an average value, a middle value, and a mode value of the normalized row data.

According to another aspect of the present invention, there is provided a method of driving a touch sensor including detecting and outputting row data for each touch node using a readout signal for each channel received from a touch sensor; Comparing the raw data with a reference value to determine whether or not the touch is present, calculating and outputting touch coordinates according to the touch presence / absence determination result; Collecting the touch node-specific row data for a plurality of frames, and resetting the reference value using row data included in the reference range among the collected row data; And the reference value is reset every time the power is turned on.

The step of resetting the reference value may include collecting the touch node-specific raw data for a plurality of frames; Normalizing the row data included in the first reference range among the collected row data; Setting any one of the row data included in the second reference range among the normally distributed row data as a base value and resetting the reference value using the set base value.

And the first reference range is set to a range that the row data can have in the absence of a touch.

And the second reference range is set to m ± nσ (n is a natural number) when the average of the normally distributed row data is m and the standard deviation is σ.

The step of resetting the reference value may include collecting the touch node-specific raw data for a plurality of frames; Normalizing the collected raw data; Setting one of the row data included in the reference range among the normally distributed row data as a base value and resetting the reference value using the set base value; And the reference range is set to m + n (n is a natural number) when the average of the normally distributed row data is m and the standard deviation is?.

The base value is set to one of an average value, a middle value, and a mode value of the normalized row data.

The present invention adaptively resets a reference value serving as a criterion for touch existence determination in consideration of external environmental conditions such as noise. Also, even if a touch occurs at the resetting of the reference value, the touch sensing sensitivity and accuracy are improved by excluding the row data corresponding to the touch from the reference value calculation process. The present invention can set an optimal reference value according to the environment of the user. In addition, it improves the sensitivity and accuracy of touch sensing even in the manufacturing process variation, component variation, and changes in external environmental conditions such as noise.

1 is a block diagram showing a configuration of a display device including a touch sensor driving apparatus according to an embodiment of the present invention.
FIG. 2 is a view showing the structure of the touch sensor 20 shown in FIG. 1, for example.
Fig. 3 is a configuration diagram of the touch controller 30 shown in Fig.
FIG. 4 is a flowchart showing a step of resetting the reference value by the touch determination unit 42 of the touch controller 30 shown in FIG.
5 is a graph showing raw data according to whether or not a touch is made to explain the setting of the first reference range.
6 is a curve obtained by normalizing the raw data.
FIG. 7 is a flowchart showing another method of resetting the reference value by the touch determination unit 42 of the touch controller 30 shown in FIG. 3 step by step.
8 is a curve obtained by normalizing the raw data.
9 is a histogram graph of row data.

Hereinafter, an apparatus and method for driving a touch sensor according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a configuration of a display device including a touch sensor driving device according to an embodiment of the present invention. FIG. 2 is a diagram showing the structure of the touch sensor 20 shown in FIG.

1 includes a touch sensor 20 on a display panel 10, a panel driver 12 including a data driver 12 and a gate driver 14 for driving the display panel 10, A timing controller 18 for controlling the panel driving unit 16; a touch sensor 20 on the display panel 10; and a touch controller 30 for driving the touch sensor 20. The timing controller 18 and the touch controller 30 are connected to the host computer 50. The touch sensor 20 of FIG. 1 may be an on-cell touch sensor attached to the upper portion of the display panel 20 or an in-cell touch sensor built in the pixel matrix, have.

The touch sensor 20 detects a user touch and allows the user to talk with the GUI displayed on the display panel 10. [ The touch sensor 20 mainly uses a capacitive type touch sensor that recognizes a touch by sensing a change in capacitance caused by a small amount of charge moving to a touch point when a conductor such as a human body or a stylus is touched. Although the touch sensor 20 shown in Fig. 1 is mounted on the display panel 10, the touch sensor 20 of the present invention is not limited to this, and the touch sensor 20 of the in-cell type May be a touch sensor.

For example, the capacitive touch sensor 20 attached on the display panel 10 may include a plurality of first sensing electrodes 22 disposed in the lateral direction as shown in FIG. 2, A plurality of lead-out lines (or reception lines) RX1 to RXm (or RX1 to RXm) in which a plurality of second sensing electrodes 24 arranged in the longitudinal direction are electrically connected to each other, ). Each of the first and second sensing electrodes 22 and 24 is mainly formed in a rhombic shape and may be formed in various other shapes. The first and second sensing electrodes 22 and 24 are driven by the touch controller 30 to form a capacitance by a fringe field and a capacitor with a conductive touch object touching the touch sensor 20 And outputs a readout signal indicating whether or not the touch is made to the touch controller 30 by changing the capacitance.

The touch controller 30 supplies a driving signal to the scan lines TX1 to TXN of the touch sensor 20 and also generates a touch signal by using a read out signal outputted from the lead- out lines RX1 to RXm of the touch sensor 20. [ Determines whether or not to touch each node (by channel), calculates the touch coordinates according to the result, and supplies the coordinate to the host computer 50.

The touch controller 30 converts the readout signals received for each channel from the lead-out lines RX1 to RXm into digital low data every time the scan lines TX1 to TXN of the touch sensor 20 are driven, And outputs low data. The touch controller 30 compares the row data for each touch node with a preset reference value to determine whether or not to touch the touch node. However, the touch controller 30 adaptively resets the reference value in consideration of external environmental conditions such as noise, and performs an operation of resetting the reference value every time the power is turned on. Accordingly, the embodiment of the present invention improves the touch sensing sensitivity and accuracy. The touch controller 30 will be described later in detail with reference to Figs. 3 to 9. Fig.

The timing controller 18 and the data driver 12 may be integrated into respective integrated circuits (ICs), or the timing controller 18 may be embedded in the data drivers 12 and integrated into one IC. The touch controller 30 and the timing controller 18 may be integrated into respective ICs or the touch controller 30 may be embedded in the timing controller 18 and integrated into one IC.

The display panel 10 includes a pixel array in which a plurality of pixels are arranged. The pixel array displays a graphical user interface (GUI) and other images including pointers or cursors. As the display panel 10, a flat panel display panel such as a liquid crystal display panel (hereinafter referred to as a liquid crystal panel), a plasma display panel, and an organic light emitting diode display panel can be mainly used. Hereinafter, a liquid crystal panel will be described as an example.

When a liquid crystal panel is used as the display panel 10, the display panel 10 includes a color filter substrate on which a color filter array is formed, a thin film transistor substrate on which a thin film transistor array is formed, a liquid crystal layer between the color filter substrate and the thin film transistor substrate And a polarizing plate attached to the outer surfaces of the color filter substrate and the thin film transistor substrate, respectively. The display panel 10 displays an image through a pixel matrix in which a plurality of pixels are arranged. Each pixel implements a desired color by a combination of red, green, and blue sub-pixels that adjust the light transmittance by varying the liquid crystal array according to the data signal. Each sub pixel includes a thin film transistor TFT connected to the gate line GL and the data line DL, a liquid crystal capacitor Clc connected in parallel with the thin film transistor TFT, and a storage capacitor Cst. The liquid crystal capacitor Clc charges the difference voltage between the data signal supplied to the pixel electrode through the thin film transistor TFT and the common voltage Vcom supplied to the common electrode, drives the liquid crystal according to the charged voltage, . The storage capacitor Cst stably maintains the voltage charged in the liquid crystal capacitor Clc. The liquid crystal layer is driven by a vertical electric field such as a TN (Twisted Nematic) mode or VA (Vertical Alignment) mode, or by a horizontal electric field such as an IPS (In-Plane Switching) mode or an FFS (Fringe Field Switching) mode.

The data driver 12 supplies video data from the timing controller 18 to a plurality of data lines DL of the display panel 10 in response to a data control signal from the timing controller 18. [ The data driver 12 converts the digital data input from the timing controller 18 into a positive / negative analog data signal by using a gamma voltage, and outputs a data signal to the data line DL). The data driver 12 includes at least one data IC and is mounted on a circuit film such as TCP, COF, FPC or the like to be attached to the display panel 10 by TAB (Tape Automatic Bonding) On the display panel 10 as shown in Fig.

The gate driver 14 sequentially drives the plurality of gate lines GL formed in the thin film transistor array of the display panel 10 in response to the gate control signal from the timing controller 18. [ The gate driver 14 supplies the gate-on voltage during a corresponding scan period of each gate line GL and supplies the gate-off voltage during the remaining period during which the other gate line GL is driven. The gate driver 14 includes at least one gate IC and is mounted on a circuit film such as a tape carrier package (TCP), a chip on film (COF), or a flexible printed circuit (FPC) Automatic bonding, or may be mounted on the display panel 10 in a COG (Chip On Glass) manner. In addition, the gate driver 14 may be embedded in the display panel 10 in a GIP (Gate In Panel) manner and formed on the thin film transistor substrate together with the pixel array.

The timing controller 18 processes the video data input from the host computer 50 and supplies the video data to the data driver 12. [ For example, in order to improve the response speed of the liquid crystal, the timing controller 18 corrects the data by overdriving driving to add an overshoot value or an undershoot value according to the data difference between adjacent frames, can do. The timing controller 18 is connected to the data driver 12 using a plurality of synchronizing signals input from the host computer 50, that is, a vertical synchronizing signal Vsync, a horizontal synchronizing signal Hsync, a data enable signal, ) And a gate control signal for controlling the driving timing of the gate driver 14 are generated. The timing controller 18 outputs the generated data control signal and gate control signal to the data driver 12 and the gate driver 14, respectively. The data control signal includes a source start pulse and a source sampling clock for controlling the latch of the data signal, a polarity control signal for controlling the polarity of the data signal, and a source output enable signal for controlling the output period of the data signal. The gate control signal includes a gate start pulse and gate shift clock for controlling the scanning of the gate signal, a gate output enable signal for controlling the output period of the gate signal, and the like. The timing controller 18 supplies the synchronizing signal (the vertical synchronizing signal Vsync and the horizontal synchronizing signal Hsync) to the touch controller 30 and controls the driving timing of the liquid crystal panel 10 and the driving timing of the touch sensor 20 So that the operation timing of the touch controller 30 can be controlled.

The host computer 50 supplies image data and a plurality of synchronizing signals to the timing controller 18, analyzes the touch coordinates inputted from the touch controller 30, and executes a command corresponding to the touch operation of the user.

Fig. 3 is a configuration diagram of the touch controller 30 shown in Fig.

3 includes a lead-out IC 32 and an MCU 40. The MUC 40 includes a touch determination unit 42, a touch coordinate calculation unit 44, an interface unit 46 .

The lead-out IC 32 supplies driving signals to the scan lines TX1 to TXN of the touch sensor 20 and also uses the lead-out signals outputted from the lead-out lines RX1 to RXm of the touch sensor 20 Thereby detecting the row data for each touch node.

The MCU 40 determines whether or not the touch is made using the row data from the lead-out IC 32, calculates the touch coordinates according to the result, and supplies it to the host computer 50. Further, the MCU 40 resets the reference value every time the power is turned on.

The touch determination unit 42 compares the row data from the lead-out IC 32 with a preset reference value to determine whether or not the touch is present. The touch determination unit 42 determines that the raw data is in the touch state if the row data is greater than or equal to the reference value and determines that the touch data is not in the row data when the row data is less than the reference value. The touch determination unit 42 determines the presence or absence of a touch using the reference value that has been adaptively reset in consideration of external environmental conditions. This improves the sensitivity and accuracy of the touch sensing.

The touch coordinate calculator 44 calculates the touch coordinate value (XY coordinate value) using the touch row data, which is the touch state from the touch determiner 42, and supplies it to the host computer through the interface unit 46. [ The touch coordinate calculator 44 calculates touch coordinate values XY (XY) based on the position information (X coordinate) of the reception line RX to which the touch row data has been output and the position information (Y coordinate) Coordinates).

FIG. 4 is a flowchart showing a step of resetting the reference value by the touch determination unit 42 of the touch controller 30 shown in FIG.

In step S10 (S10) and step S20 (S20), the touch determination unit 42 collects row data per touch node for a plurality of frames. The touch determination unit 42 compares the collected row data with the first reference range, and continuously collects row data when there is no value included in the first reference range of the row data. As shown in Fig. 5, the first reference range is set to a range that the row data can have in the absence of touch. At this time, the row data collected by the touch determination unit 42 may include both the raw data in the touch state and the row data in the touch state. However, the touch determination unit 42 filters the raw data in the touch state in order to use only the row data in a state in which there is no touch at the time of calculating the reference value, which will be described later in detail.

In step 30 (S30), the touch determination unit 42 deletes row data that are out of the first reference range among the collected row data, if any. Accordingly, among the row data collected by the touch determination unit 42, the row data in the touch state is erased and excluded from the calculation of the reference value. Then, the touch determination unit 42 normalizes the row data included in the first reference range, as shown in FIG.

In step 40 (S40), the touch determination section 42 sets the second reference range. When the average of the normally distributed row data is m and the standard deviation is σ, the second reference range is m ± nσ (n is a natural number), for example, m ± σ or m ± 2σ or m ± 3σ Respectively.

In step 50 (S50), the touch determination unit 42 deletes the row data out of the second reference range out of the normally distributed row data. And sets one of the row data included in the second reference range as a base value. When the second reference range is set to m ± σ, about 68.2% of the normally distributed row data is included in the second reference range. And when the second reference range is set to m + - 2σ, about 95.9% of the normalized row data is included in the second reference range. And when the second reference range is set to m + 3σ, about 99.7% of the normally distributed row data is included in the second reference range. Meanwhile, the base value may be set to any one of an average value, a middle value, and a mode value of the normally distributed row data.

In step 60 (S60), the touch determination unit 42 sets a reference value based on the base value. The touch determination unit 42 sets the reference value to a value higher than the base value by a predetermined value in consideration of the capacitance change in the touch state based on the base value.

FIG. 7 is a flowchart showing another method of resetting the reference value by the touch determination unit 42 of the touch controller 30 shown in FIG. 3 step by step.

In step S10 (S10), the touch determination unit 42 collects row data per touch node for a plurality of frames. At this time, the row data collected by the touch determination unit 42 may include both the raw data in the touch state and the row data in the touch state. However, the touch determination unit 42 filters the raw data in the touch state in order to use only the row data in a state in which there is no touch at the time of calculating the reference value, which will be described later in detail.

In step S20 (S20), the touch determination unit 42 normalizes the collected row data as shown in FIG.

In step 30 (S30), the touch determination unit 42 sets the reference range. When the average of the normally distributed row data is m and the standard deviation is σ, the reference range is set to m ± nσ (n is a natural number), for example, m ± σ or m ± 2σ or m ± 3σ.

In step 40 (S40), the touch determination unit 42 deletes the row data out of the reference range out of the normally distributed row data. Then, one of the row data included in the reference range is set as the base value. When the reference range is set to m ± σ, about 68.2% of the normally distributed row data is included in the second reference range. And when the reference range is set to m + - 2 [sigma], about 95.9% of the normalized row data is included in the reference range. And when the reference range is set to m + - 3 sigma, about 99.7% of the normalized row data is included in the reference range.

For reference, even if the user touches the touch panel during the resetting of the reference value, the ratio of the low data which is the touch-free state in the entire row data is extremely small. This can be easily seen by histogramming the collected raw data, as shown in Fig. Referring to FIG. 9, it can be seen that the frequency of the raw data in the touch state is lowest compared to other row data. Therefore, if the touch determination unit 42 erases the row data out of the reference range (m + -? Or m + - 2? Or m + 3?) Out of the normally distributed row data in step 40 (S40) Low data is erased.

Meanwhile, the base value may be set to any one of an average value, a middle value, and a mode value of the normally distributed row data.

In step 50 (S50), the touch determination unit 42 sets a reference value based on the base value. The touch determination unit 42 sets the reference value to a value higher than the base value by a predetermined value in consideration of the capacitance change in the touch state based on the base value.

As described above, the present invention adaptively resets the reference value, which is a criterion of touch existence determination, in consideration of external environmental conditions such as noise. Also, even if a touch occurs at the resetting of the reference value, the touch sensing sensitivity and accuracy are improved by excluding the row data corresponding to the touch from the reference value calculation process. The present invention can set an optimal reference value according to the environment of the user. In addition, it improves the sensitivity and accuracy of touch sensing even in the manufacturing process variation, component variation, and changes in external environmental conditions such as noise.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. Will be clear to those who have knowledge of.

10: liquid crystal panel 12: data driver
14: gate driver 16: panel driver
18: timing controller 20: touch sensor
22: first sensing electrode 24: second sensing electrode
30: Lead-out controller 32: Lead-out IC
40: MCU 42: touch judgment unit
44: touch coordinate calculation unit 46: interface unit
50: Host computer

Claims (13)

A touch sensor;
A readout circuit for driving the touch sensor and detecting and outputting row data for each touch node using a readout signal for each channel received from the touch sensor;
A signal processor for comparing the row data provided from the lead-out circuit with a preset reference value to determine whether or not a touch is present, calculating and outputting touch coordinates according to the touch presence / absence determination result, and resetting the reference value each time the power is turned on and;
Wherein the signal processor collects the touch-node-specific row data for a plurality of frames and resets the reference value using raw data included in a reference range of the collected row data. The method according to claim 1,
The signal processor
A touch determination unit for determining whether the touch exists or not and resetting the reference value;
A touch coordinates calculation unit for calculating the touch coordinates;
And an interface unit for relaying the touch coordinate output. The method of claim 2,
The touch determination unit
The method comprising the steps of: collecting the touch node-specific low data during a plurality of frames; normalizing the low data included in the first reference range among the collected low data; Sets one of the data as a base value, and resets the reference value using a set base value. The method of claim 3,
Wherein the first reference range is set to a range that the row data can have in the absence of a touch. The method of claim 3,
Wherein when the average of the normally distributed row data is m and the standard deviation is σ, the second reference range is set to m ± nσ (n is a natural number). The method of claim 2,
The touch determination unit
The method includes the steps of: collecting row data for each touch node during a plurality of frames in a state in which there is no touch, normalizing the collected row data, and selecting any one of row data included in the reference range among the normally- , The reference value is reset using the set base value,
Wherein when the average of the normally distributed row data is m and the standard deviation is σ, the reference range is set to m ± nσ (n is a natural number). The method according to claim 3 or 6,
The base value
And the average value, the median value, and the mode value of the normally distributed row data. Detecting and outputting row data for each touch node using a readout signal for each channel received from the touch sensor;
Comparing the raw data with a reference value to determine whether or not the touch is present, calculating and outputting touch coordinates according to the touch presence / absence determination result;
Collecting the touch node-specific row data for a plurality of frames, and resetting the reference value using row data included in the reference range among the collected row data;
And resetting the reference value every time the power is turned on. The method of claim 8,
The step of resetting the reference value
Collecting the touch node-specific raw data for a plurality of frames;
Normalizing the row data included in the first reference range among the collected row data;
Setting one of the row data included in the second reference range among the normally distributed row data as a base value and resetting the reference value using the set base value. Driving method. The method of claim 9,
Wherein the first reference range is set to a range that the row data can have in the absence of a touch. The method of claim 9,
Wherein when the average of the normally distributed row data is m and the standard deviation is σ, the second reference range is set to m ± nσ (n is a natural number). The method of claim 8,
The step of resetting the reference value
Collecting the touch node-specific raw data for a plurality of frames;
Normalizing the collected raw data;
Setting one of the row data included in the reference range among the normally distributed row data as a base value and resetting the reference value using the set base value;
Wherein when the average of the normally distributed row data is m and the standard deviation is σ, the reference range is set to m ± nσ (n is a natural number). The method according to claim 9 or 12,
The base value
And the average value, the median value, and the mode value of the normalized row data.

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