KR102117670B1 - Touch screen driving apparatus and method - Google Patents

Abstract

The present invention provides a touch screen including Tx lines and Rx lines intersecting the Tx lines, supplying a driving pulse to the Tx lines, converting a sensing voltage for the Rx lines into digital data, and setting a preset touch algorithm And a touch controller generating touch coordinates from the digital data, wherein the touch controller supplies driving pulses in a low power mode to Tx lines outside a predetermined range from touch coordinates generated in the previous frame. Provided is a touch screen driving device.

Description

Touch screen driving device and method {TOUCH SCREEN DRIVING APPARATUS AND METHOD}

The present invention relates to a technology for driving a touch screen.

With the reduction in weight and slimness of the display device, a touch screen technology that replaces a keyboard and a mouse that occupies additional weight and space is gradually being introduced. This touch screen technology can recognize a user's manipulation in the same location as the image displayed on the screen, thereby providing a highly intuitive user interface.

1 is a view showing a method of driving a touch screen. 1 (a), (b), (c), and (d) show touch screen driving in four consecutive frames, respectively.

Referring to (a) of FIG. 1, the display device sequentially supplies driving pulses to each Tx line in the first frame and sequentially senses voltage to each Rx line. In the first frame, there is no user's touch.

Referring to (b) of FIG. 1, a user's touch occurs at a node where the Tx2 line and the Rx2 line intersect in the second frame. As in the first frame, the display device sequentially supplies driving pulses to each of the Tx lines in the second frame and sequentially senses a voltage for each of the Rx lines to recognize the user's touch. When the touch is recognized by the capacitive method, the display device recognizes the touch using the effect that the voltage at the node where the user's touch occurs is smaller than the voltage at the other node.

Referring to (c) of FIG. 1, the user's touch position moves in the third frame, and the user's touch occurs at a node where the Tx2 line and the Rx3 line intersect. At this time, as in the previous frame, the display device sequentially supplies driving pulses to each Tx line and sequentially senses a voltage to each Rx line to recognize a user's touch.

Referring to (d) of FIG. 1, the user's touch position continues to move in the fourth frame, and the user's touch occurs at a node where the Tx2 line and the Rx4 line intersect. At this time, the display device sequentially supplies driving pulses to each of the Tx lines as in the previous frame and sequentially senses a voltage to each of the Rx lines to recognize the user's touch.

As illustrated in FIG. 1, the user's touch position may be continuously changed. However, since the user's movement speed has a physical limitation, the touch position fluctuation between frames is also limited. Referring to FIG. 1, the touch position is moved from Rx2 to Rx3 between the second frame and the third frame, so that only one Rx line interval is moved. In addition, even between the third frame and the fourth frame, the touch position is moved only by one Rx line interval (moved from Rx3 to Rx4). Although the touch position variation in FIG. 1 is an example, the touch position cannot be rapidly changed in a continuous frame. This comes from the physical limitations of the user's movement speed, as described above.

As such, since the amount of change in the touch position is limited, the Tx lines and Rx lines used to sense the touch are also limited. Referring to the example of FIG. 1, in three consecutive frames, the touch position moves only on the Rx2, Rx3, and Rx4 lines based on the Rx line, and if the display device senses only these three Rx lines, the touch position can be determined. do.

However, although the location where the touch occurs is limited, the display device illustrated in FIG. 1 supplies driving pulses to the entire Tx line every frame and senses a voltage to the entire Rx line. The display device of FIG. 1 has a problem in that power is excessively used by supplying driving pulses and sensing voltages to Tx lines and Rx lines that are less likely to be used for touch sensing.

Against this background, it is an object of the present invention to, in one aspect, provide a technique for a device that drives a touch screen with low power.

In another aspect, an object of the present invention is to provide a technique for selectively driving a low power mode for an area that is less likely to be touched.

In another aspect, an object of the present invention is to provide a technique for increasing the sensing speed by reducing the sensing time.

In order to achieve the above object, in one aspect, the present invention provides a touch screen including Tx lines and Rx lines intersecting the Tx lines; And a touch controller that supplies driving pulses to the Tx lines, converts the sensing voltage for the Rx lines to digital data, and generates touch coordinates from the digital data according to a preset touch algorithm, wherein the touch controller is Provided is a touch screen driving apparatus characterized by supplying a driving pulse in a low power mode for Tx lines outside a predetermined range from touch coordinates generated in a frame.

In another aspect, the present invention provides a method of driving a touch screen including Tx lines and Rx lines intersecting the Tx lines, the method comprising: supplying a driving pulse to the Tx lines; Converting sensing voltages of the Rx lines into digital data; And generating touch coordinates from the digital data according to a preset touch algorithm, and in the step of supplying the driving pulse, in a low power mode for Tx lines outside a predetermined range from touch coordinates generated in the previous frame. It provides a touch screen driving method characterized in that it supplies a driving pulse.

As described above, according to the present invention, there is an effect of driving the touch screen with low power. In addition, according to the present invention, it is possible to reduce power consumption without lowering the accuracy of sensing by selectively driving a low power mode for an area that is unlikely to be touched. In addition, according to the present invention, the overall sensing time can be shortened to shorten the time of one frame, and accordingly, the sensing speed can be increased.

1 is a view showing a method of driving a touch screen.
2 is a block diagram of a display device according to an exemplary embodiment.
3 is an electrode layout diagram of the touch screen of FIG. 2.
4 is a control flowchart of a touch sensing method in which N scans are performed for one Tx line of FIG. 3.
FIG. 5 is a diagram illustrating differently controlling the number of scans N for each Tx line in FIG. 3.
6 is a control flowchart for a method of differently controlling the number of scans N for each Tx line of FIG. 3.
7 is a view for explaining a method for setting a low power mode region.
8 is a diagram illustrating driving in a low power mode for the Tx line and the Rx line.
FIG. 9 is a diagram illustrating driving in a low power mode with respect to the Tx line and the Rx line when performing group unit sensing.
10 is a flowchart of control for selectively performing normal sensing and low power sensing depending on the presence or absence of touch.
11 is a waveform diagram of a driving signal for explaining embodiments of a low power mode scan for a Tx line.
12 is a waveform diagram in an embodiment in which a low power mode is applied in units of frames.

DETAILED DESCRIPTION Embodiments of touch screen driving for recognizing that a user's body (eg, a finger) or an object controlled by a user (eg, a touch pen) touch the screen will be described. In particular, description will be given of touch screen driving embodiments in which areas in which a touch is unlikely to occur are set in consideration of physical limitations in which a user's body can move, and the sensitivity of touch sensing to the areas is reduced.

Hereinafter, some embodiments of the present invention will be described in detail through exemplary drawings. It should be noted that in adding reference numerals to the components of each drawing, the same components have the same reference numerals as possible even though they are displayed on different drawings. In addition, in describing embodiments of the present invention, when it is determined that detailed descriptions of related well-known configurations or functions may obscure the subject matter of the present invention, detailed descriptions thereof will be omitted.

In addition, in describing the components of the invention, terms such as first, second, A, B, (a), and (b) can be used. These terms are only for distinguishing the component from other components, and the nature, order, or order of the component is not limited by the term. When a component is described as being "connected", "coupled" or "connected" to another component, that component may be directly connected to or connected to the other component, but another component between each component It will be understood that elements may be "connected", "coupled" or "connected". In the same vein, when it is stated that a component is formed "above" or "below" another component, that component is all formed directly or indirectly through another component. It should be understood as including.

2 is a block diagram of a display device according to an exemplary embodiment, and FIG. 3 is an electrode layout diagram of the touch screen of FIG. 2.

Referring to FIG. 2, the display device 200 includes a display panel 290 and a driver circuit 292 (driver IC) and a timing controller 294 and T-con for displaying images on the display panel 290. You can.

The display device 200 includes a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP), and an organic light emitting display (Organic Light Emitting Display). OLED), an electrophoretic display device (Electrophoresis, EPD), and the like. In the following embodiments, as an example of a flat panel display element, a display device is mainly described as a liquid crystal display element, but it should be noted that the display device 200 of the present invention is not limited to a liquid crystal display element.

The display panel 290 may have a liquid crystal layer formed between two substrates. The lower substrate of the display panel 290 includes a plurality of data lines, a plurality of gate lines intersecting the data lines, a plurality of TFTs (Thin Film Transistor) formed at intersections of the data lines and the gate lines, and a liquid crystal. It may include a plurality of pixel electrodes for charging the data voltage to the cells, a storage capacitor connected to the pixel electrode to maintain the voltage of the liquid crystal cell, and the like.

The pixels of the display panel 290 may be formed in a pixel area defined by data lines and gate lines and may be arranged in a matrix form. Each liquid crystal cell of each pixel is driven by an electric field applied according to a voltage difference between a data voltage applied to the pixel electrode and a common voltage applied to the common electrode to control the amount of transmitted incident light. The TFTs are turned on in response to the gate pulse from the gate line to supply the voltage from the data line to the pixel electrode of the liquid crystal cell.

The upper substrate of the display panel 290 may include a black matrix, a color filter, or the like. The lower substrate of the display panel 290 may be implemented in a color filter on TFT (COT) structure. In this case, the black matrix and the color filter may be formed on the lower substrate of the display panel 290.

A polarizing plate is attached to each of the upper and lower substrates of the display panel 290 and an alignment layer for setting a pretilt angle of the liquid crystal may be formed on an inner surface contacting the liquid crystal. A column spacer for maintaining a cell gap of a liquid crystal cell may be formed between the upper substrate and the lower substrate of the display panel 290.

The driver circuit 292 may convert the digital video data RGB input from the timing controller 294 into an analog positive / negative gamma compensation voltage and output a data voltage. The data voltage is supplied to the data lines. The driver circuit 292 also sequentially supplies gate pulses synchronized with the data voltage to the gate lines to select a line of the display panel 290 to which the data voltage is written.

The timing controller 294 receives timing signals such as a vertical synchronization signal (Vsync), a horizontal synchronization signal (Hsync), a data enable signal (Data Enable, DE), and a main clock (MCLK) input from the host 240. A scan timing control signal and a data timing control signal for controlling the operation timing of the driver circuit 292 may be generated. The scan timing control signal may include a gate start pulse (GSP), a gate shift clock (Gate Shift Clock), a gate output enable signal (Gate Output Enable, GOE), and the like. The data timing control signal may include a source sampling clock (Source Sampling Clock, SSC), a polarity control signal (Polarity, POL), a source output enable signal (Source Output Enable, SOE), and the like.

The above-described portions are components related to displaying an image on the screen in the display device 200. While continuing referring to FIG. 2, a configuration related to sensing a touch on the display device 200 will be described.

The display device 200 may include a touch screen 210 and a touch circuit 220 for sensing a touch on the touch screen 210 and a microcontrol unit 230 and an MCU. The touch IC 220 and the MCU 230 (micro control unit) may be collectively referred to as a touch controller, but the present invention is not limited by these names.

In FIG. 2, the touch IC 220 and the microcontrol unit (MCU 230) are shown to be separated, but the touch IC 220 and the MCU 230 may be configured as one controller. Hereinafter, an embodiment in which the touch IC 220 and the MCU 230 are separated for convenience of description will be described. However, as described above, the touch IC 220 and the MCU 230 may be implemented as a single controller, and some of the functions performed by the touch IC 220 may be performed by the MCU 230 and the MCU 230 Some of the functions performed by the touch IC 220 may be performed.

The touch screen 210 may be bonded on the upper polarizing plate of the display panel 290 or may be formed between the upper polarizing plate and the upper substrate. In addition, the electrodes of the touch screen 210 (Tx lines Tx1 to Tx6 and Rx lines Rx1 to Rx8 in FIG. 3) are in-cell together with a pixel array in the display panel 290. It can be formed on the lower substrate as a type.

The touch screen 210 may include Tx lines Tx1 to Tx6, Rx lines Rx1 to Rx8 intersecting the Tx lines, and sensor nodes formed at intersections of the Tx lines and Rx lines. The number of Tx lines and Rx lines in FIG. 3 is exemplary, and the touch screen 210 may include J (J is a natural number of 1 or more) Tx lines and K (K is a natural number of 1 or more) Rx lines. have.

The touch IC 220 may supply driving pulses to the Tx lines Tx1 to Tx6 and sense the voltage of the sensor node through the Rx lines Rx1 to Rx8 to convert it into digital data. The circuit for supplying the driving pulse to the Tx lines (Tx1 to Tx6) and the circuit for sensing the voltage of the Rx lines (Rx1 to Rx8) may be configured as separate ICs, but one ROIC as illustrated in FIG. 2 (Read-out IC).

The touch IC 220 sets a Tx channel in response to a setup signal input from the MCU 230 and supplies driving pulses to the Tx lines Tx1 to Tx6 connected to the set Tx channel. As shown in FIG. 3, if eight sensor nodes are connected to one Tx line, after the driving pulse is supplied to the Tx line eight times in succession, the driving pulses may be supplied to the next Tx line in the same manner.

When supplying a driving pulse to a sensor node connected to one Tx line once is called a scan, the touch IC 220 performs two or more scans (for example, 10 scans) on one Tx line. Can be. The touch IC 220 may perform multiple scans on one Tx line and perform multiple scans on the next Tx line in the same manner.

The touch IC 220 sets the Rx channel to receive the voltage of the sensor node in response to the setup signal input from the MCU 230, and senses the voltage of the sensor node through the Rx line connected to the set Rx channel. The touch IC 220 may convert the voltage of the sensed sensor node into touch raw data, which is digital data, and transmit it to the MCU 230.

The MCU 230 may be connected to the touch IC 220 through interfaces such as an I2C bus, a serial peripheral interface (SPI), and a system bus. The MCU 230 supplies a setup signal to the touch IC 220 to set a Tx channel to output a driving pulse and selects an Rx channel from which the voltage of the sensor node is read. The MCU 230 may control the voltage sampling timing of the sensor node by supplying the Rx sampling clock for controlling the switches of the sampling circuit built in the touch IC 220 to the touch IC 220. In addition, the MCU 230 may control the operation timing of the ADC by supplying the ADC clock to an analog-to-digital converter built into the touch IC 220.

The MCU 230 analyzes touch input data input from the touch IC 220 with a preset touch algorithm, estimates coordinate values for touch data having a predetermined reference value or higher, generates touch data including coordinate information, and hosts 240 ).

The host 240 is connected to an external video source device, for example, a navigation system, a set-top box, a DVD player, a Blu-ray player, a personal computer (PC), a home theater system, a broadcast receiver, a phone system, and the like. Video data can be input from a video source device. The host 240 converts image data from an external video source device to a format suitable for display on the display panel 290, including a system on chip (SoC) including a scaler. In addition, the host 240 may execute an application program associated with coordinate values of touch data input from the MCU 230.

4 is a control flowchart of a touch sensing method in which N scans are performed for one Tx line of FIG. 3.

Referring to FIG. 4, the touch IC 220 supplies a driving pulse to one Tx line (S402). At this time, the touch IC 220 may supply driving pulses as many as the number of Rx lines. For example, referring to FIG. 3, since there are eight Rx lines on the touch screen 210, the touch IC 220 may supply eight driving pulses for one Tx line.

The touch IC 220 sequentially senses the voltage of each Rx line in response to the driving pulse supplied to the Tx line (S404). When a touch is sensed by a capacitive type, the capacitance of the Rx line connected to the corresponding sensor node is sensed at a sensor node where a touch occurs, and the voltage of the Rx line connected to the sensor node is sensed less than the voltage of the other Rx line. The display device 200 determines the location of the touch using the principle that the sensing voltage of the Rx line is differently sensed.

When the driving pulse is supplied to one Tx line and the voltage is sensed for each Rx line is referred to as scan, the touch IC 220 may perform N scans for one Tx line. Accordingly, if the counter value is greater than N while increasing the counter (YES in S406), the touch IC 220 ends the scan for one Tx line, and when the counter value becomes smaller than N (NO in S406), S402 And S404, the scan may be performed again.

FIG. 5 is a diagram illustrating differently controlling the number of scans N for each Tx line in FIG. 3. In FIG. 5, (b) shows the touch screen driving of the next frame successive to (a). For convenience of description, FIG. 5 (a) is referred to as a first frame and FIG. 5 (b) is referred to as a second frame.

Referring to FIG. 5, the touch IC 220 performs L scans for the entire Tx line in the first frame, and scans L times for the Tx2, Tx3, and Tx4 lines in the second frame and the remaining Tx lines For (Tx1, Tx5 and Tx6 lines), S scans are performed. Here, L and S are natural numbers, and L has a value greater than S.

The MCU 230 may control the number of scans of the touch IC 220 by controlling the touch IC 220. In the embodiment shown in FIG. 5, the MCU 230 may perform L times for the entire area in the first frame. Scanning is performed to recognize the touch, and in the second frame, the area of the touch screen 210 is divided to scan L times in one area (Tx2, Tx3, and Tx4 line areas), but another area (Tx1, Tx5, and Tx6 line areas) In), the number of scans is controlled differently for each Tx line by performing S scan.

When the scan mode in the first frame is regarded as an example of the normal mode, and the scan mode in the second frame is regarded as an example of the low power mode, the MCU 230 controls the first time until the touch is first generated. After the normal mode scan is performed as in the first frame, after the touch occurs, the low power mode scan may be performed as in the second frame.

6 is a control flowchart for a method of differently controlling the number of scans N for each Tx line of FIG. 3. 6 is a flowchart of a control method in a second frame corresponding to (b) of FIG. 5.

The MCU 230 checks the touch coordinates in the previous frame (S602). Then, a Tx line to be scanned is selected (S604), and the number of scans according to the Tx line is determined based on the identified touch coordinates (S606). When following the example described with reference to FIG. 5, the MCU 230 determines the number of scans for the Tx1, Tx5, and Tx6 lines as S times in step S606, and the number of scans for the Tx2, Tx3, and Tx4 lines is L times. You can decide.

After determining the number of scans, the MCU 230 controls the touch IC 220 to cause the touch IC 220 to scan for each Tx line by the determined number of scans as described with reference to FIG. 4.

When scanning is performed for each Tx line (NO in S614), and scanning is performed to the last Tx line (YES in S614), the MCU 230 generates touch data including coordinate information (S616). At this time (S616), the generated touch data may be transmitted to the host 240 (S618), and when repeating the control as shown in FIG. 6 in the next frame, it is utilized as touch coordinate information of the previous frame (utilized in step S602). .

5 and 6, an embodiment of a method of differently controlling the number of scans for each Tx line has been described. Next, a description will be given of a method of setting an area for controlling a small number of scans in this control method.

7 is a diagram for explaining a method for setting a low power mode region.

The MCU 230 is divided into areas within a predetermined distance 710 from the touch position 520 in the previous frame (720, hereinafter referred to as "normal mode area") and other areas (hereinafter referred to as "low power mode area"). Separately, the Tx line overlapping the normal mode area is scanned in the normal mode (for example, L scan in the above example), and the Tx line overlapping the low power mode area and the normal mode scan is not performed is the low power mode. You can scan to (eg, S times in the above-described example).

The division of the area as a predetermined distance 710 from the touch position 520 in the previous frame is based on the principle that the user's movement is physically limited. Since the user's movement is physically limited, the MCU 230 is an area within a certain distance 710 according to the principle that the touch position 530 in the current frame does not fall more than a predetermined distance from the touch position 520 in the previous frame. For the (normal mode area), more scans are performed than the other areas (low power mode area).

A certain distance can be calculated statistically through measurement data. 7B illustrates touch coordinate values generated by a user's hand moving randomly over 10 frames. Referring to (b) of FIG. 7, the touch coordinates are maximally moved between frames 9 and 10 and moved by 3 in the Tx direction, and moved by 1 in the Rx direction. Accordingly, a certain distance can be set as 3 in the Tx direction and 1 as the Rx direction. It is also possible to use a larger value (for example, 4 in the Tx direction and 2 in the Rx direction) in consideration of the margin.

The user may calculate a certain distance value through several tests and input it as a set value to the MCU 230, but the MCU 230 may automatically manage the history of touch coordinates to automatically calculate a constant distance value. For example, the MCU 230 may calculate the above-described constant distance value according to the touch coordinate value that has been moved to the maximum within the last 1000 frames. At this time, the MCU 230 does not need to store all the touch coordinates of the previous frame, but only stores the touch coordinates of the previous frame, and calculates a touch coordinate shift value according to the difference between the touch coordinates of the previous frame and the current frame. . In addition, the MCU 230 may derive the maximum value of the touch coordinate movement value by storing the touch coordinate movement value and updating the touch coordinate movement value when the touch coordinate movement value calculated for each frame is greater than the previously stored value. have.

The constant distance may be set for only one direction. For example, it is possible to set only for the Tx direction and not to distinguish regions for the Rx direction.

Meanwhile, when a predetermined distance is determined and the normal mode region and the low power mode region are distinguished, the MCU 230 may sense the voltage in the low power mode even for the Rx line.

8 is a diagram illustrating driving in a low power mode for the Tx line and the Rx line.

Referring to FIG. 8, areas in which Tx lines and Rx lines that are within a predetermined distance from the touch position 520 of the previous frame intersect are set as the normal mode area 810 and other areas are low-power mode areas 820a and 820b. , 830a and 830b).

The touch IC 220 senses the voltage of the sensor node (the point where the Tx line and the Rx line cross) in response to the driving pulse supplied to the Tx lines, since the voltage of the sensor node is sensed through the Rx line. In some cases, it was described as sensing the voltage of the Rx line. In the embodiment of FIG. 8, regions of the touch screen 210 may be distinguished for each sensor node. In the description of this, the touch IC 220 is expressed as sensing the sensor node voltage.

The touch IC 220 may supply a driving pulse in the normal mode to Tx lines overlapping the normal mode region 810. In this case, the touch IC 220 may sense the sensor node voltages of the normal mode region 810 and the sensor node voltages of the other regions 820a and 820b differently.

When the normal mode area 810 is determined by the touch coordinates of the previous frame, since the touch is likely to occur, the touch IC 220 senses the sensor node in the normal mode area 810 in the normal mode. On the other hand, the touch IC 220 may sense the sensor node voltage in a low power mode because the other regions 820a and 820b are unlikely to generate a touch. As an example, the touch IC 220 may sense a voltage by reducing a sensing time for a corresponding sensor node. As the sensing time becomes shorter, the touch IC 220 may reduce power consumption.

In the regions 830a and 830b where the driving pulse is not supplied in the normal mode, the touch IC 220 supplies the driving pulse in the low power mode for Tx lines and senses the sensor node voltage in the low power mode for Rx lines. can do.

FIG. 9 is a diagram illustrating driving in a low power mode for the Tx line and the Rx line when performing group-level sensing.

The touch IC 220 may group two or more lines together and sense a touch in a group unit. For example, Tx1 and Tx2 are grouped into a first Tx group, Tx3 and Tx4 are grouped into a second Tx group, Tx5 and Tx6 are grouped into a third Tx group, and Rx1 and Rx2 are grouped into a first Rx group, Rx3 and Rx4 are second Rx groups. The group, Rx5 and Rx6, may be grouped into a third Rx group, and Rx7 and Rx8 into a fourth Rx group. At this time, when the touch IC 220 senses a touch in a group unit, power consumed for sensing can be reduced.

Referring to FIG. 9, the touch IC 220 is in groups (first Tx group, second Tx group, first Rx group, second Rx group, third Rx group) intersecting the normal mode area 910. For the group, sensing is performed in a normal mode for individual lines without performing group-level sensing. In addition, the touch IC 220 provides group unit sensing for other groups (third Tx group and fourth Rx group) (drive pulses in group units for the Tx line, and voltages in group units for the Rx line). Sensing) to reduce power consumption.

Meanwhile, when a touch occurs in the previous frame, the MCU 230 can control the touch IC 220 by generating touch coordinates and classifying the normal mode and the low power mode according to a certain distance from the touch coordinates. When the touch does not occur in the previous frame, the MCU 230 may control the entire area in a normal mode. For convenience of description, the control of the entire area in the normal mode is referred to as normal sensing, and the control of the area in the normal mode and the low power mode is referred to as low power sensing.

10 is a flowchart of control for selectively performing normal sensing and low power sensing depending on the presence or absence of touch.

Referring to FIG. 10, the MCU 230 may manage an area flag through memory. The flag may be a boolean type variable, but is not limited thereto, and may indicate two or more values. It may be another type of variable.

If the flag is not turned ON (NO in S902), the MCU 230 proceeds to normal sensing (S904). If the touch is not sensed in the normal sensing (NO in S906), the MCU 230 performs normal sensing again (S904).

When the touch is sensed (YES in S906), the MCU 230 changes the flag to the ON state. And the MCU 230 confirms that the flag is ON (YES in S902), and proceeds with low power sensing (S910). If the touch is not sensed again in the low power sensing (NO in S906), the MCU 230 moves back to the normal sensing step (S904).

In the above, an embodiment in which the number of scans is controlled to be small for the low power mode scan of the Tx line has been described. The low power mode scan indicates that the power consumption generated when the touch IC 220 supplies the driving pulse is reduced, and is not limited to a method of reducing the number of scans.

11 is a waveform diagram of a driving signal for explaining embodiments of a low power mode scan for a Tx line.

FIG. 11A is a waveform diagram of a driving signal of a normal mode scan performed on one Tx line in one frame. Referring to (a) of FIG. 11, within one frame, the MCU 230 performs six scans. Although not shown in FIG. 11 (a), a plurality of driving pulses may be supplied to the Tx line within one scan time.

FIG. 11B is a first example of the low power mode scan, and shows that the magnitude of the driving pulse voltage in the driving signal is controlled to be small. The power consumption in driving may be proportional to the voltage or the square of the voltage, and the touch IC 220 may reduce power consumption by reducing the voltage of the driving pulse.

FIG. 11 (c) is a second example of the low power mode scan, and shows that the number of scans is controlled less. The power consumption in driving may be proportional to the number of scans, but the touch IC 220 may reduce the number of scans to reduce power consumption.

11 (d) shows that the pulse width of the driving pulse is narrowly controlled as a third example of the low power mode scan. In FIG. 11 (d), for better understanding, the pulse width of the driving pulse is narrowed, and the scan time is also shortened. However, when only the pulse width of the driving pulse is narrowed and the interval of the driving pulse is maintained, the scan time is the same as the normal mode. can do.

11 (e) is a fourth example of the low power mode scan, and shows that the third example and the first example are controlled to alternately proceed for each scan. In (e) of FIG. 11, the third example and the first example are shown alternately for the sake of understanding, but the third example and the first example are simultaneously applied, and thus, a low power is generated using a driving pulse having a small voltage and a narrow pulse width. Mode scan can also be performed.

12 is a waveform diagram in an embodiment in which a low power mode is applied in units of frames. The MCU 230 may control the driving pulses of some frames to be skipped in the low power mode, and FIG. 12 is a diagram for explaining this embodiment.

In the previous embodiments, the MCU 230 divided regions by using touch coordinates in the previous frame for each frame and performed low power sensing. However, the present invention is not limited to this. For example, the MCU 230 may perform low power sensing by using touch coordinates in a frame before two frames.

In the example of FIG. 12, the MCU 230 bundles two frames (first frame and second frame) to determine whether there is a touch, and if there is a touch, performs low power sensing in the next two frames (third frame and fourth frame). Can be.

Referring to FIG. 12, the MCU 230 generates a touch in the first frame or the second frame, and Tx2, Tx3, and Tx4 lines perform normal mode scan in the following frames, and the Tx1, Tx5, and Tx6 lines are in a low power mode. Scan. In the low power mode scan 230, the MCU 230 may control the driving pulse to be skipped in one of two frames. Accordingly, driving signals are not supplied to the Tx1, Tx5, and Tx6 lines in the fourth frame and the sixth frame.

Meanwhile, the embodiments can be applied not only to single-mode touch sensing, but also to multi-mode touch sensing. In multi-mode touch sensing, the touch coordinates of the previous frame may be two or more, and accordingly, the MCU 230 sets two or more normal mode regions and low power mode regions based on two or more touch coordinates to apply the above-described embodiments. You can.

In the above, embodiments of the touch screen driving apparatus and method for reducing power consumption by driving in a low power mode have been described. By applying these embodiments, power consumption in driving the touch screen can be reduced. In particular, if an embodiment in which only a low-touch area is selectively driven in a low power mode is applied, power consumption can be reduced without deteriorating the accuracy of touch sensing.

In addition, when driving in a low power mode in a manner such as reducing the number of scans, the signal processing load or data processing load of the touch IC 220 or MCU 230 is reduced to reduce the low cost touch IC 220 or MCU 230. It will be able to perform other functions as much as it is produced or reduced. In addition, when the number of scans is reduced, the overall sensing time is reduced, so that the time of one frame can be shortened. When the time of one frame is shortened, the sensing speed becomes faster, so that the sensing sensitivity can be further increased.

The terms "include", "compose" or "have" as described above mean that the corresponding component can be inherent unless otherwise stated, and do not exclude other components. It should be construed that it may further include other components. All terms, including technical or scientific terms, have the same meaning as generally understood by a person skilled in the art to which the present invention pertains, unless otherwise defined. Commonly used terms, such as predefined terms, should be interpreted as being consistent with the meaning of the context of the related art, and are not to be interpreted as ideal or excessively formal meanings unless explicitly defined in the present invention.

The above description is merely illustrative of the technical idea of the present invention, and those of ordinary skill in the art to which the present invention pertains may make various modifications and variations without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical spirits within the equivalent range should be interpreted as being included in the scope of the present invention.

210: TSP
220: Touch IC
230: MCU
240: host
290: display panel
292: Driver IC
294: T-con

Claims (8)

A touch screen comprising Tx lines and Rx lines;
And a touch controller that supplies driving pulses to the Tx lines, converts the sensing voltage for the Rx lines to digital data, and generates touch coordinates from the digital data according to a preset touch algorithm,
The touch controller sets a certain range based on the touch coordinates generated in the previous frame based on the maximum touch coordinate movement value between frames, sets an area within the predetermined range as a normal mode area, and sets an area outside the predetermined range. Set as a low power mode region, and supply a normal mode driving pulse for Tx lines overlapping the normal mode region, and a low power mode driving pulse for Tx lines that overlap the low power mode region and do not overlap the normal mode region. Supplying, and the driving pulse of the low power mode is different from the driving pulse of the normal mode. According to claim 1,
The touch controller,
The voltage level of the driving pulse of the low power mode is smaller than the voltage of the driving pulse of the normal mode, or the pulse width of the driving pulse of the low power mode is controlled to be narrower than the pulse width of the driving pulse of the normal mode. Touch screen driving device. According to claim 1,
The touch controller,
And controlling the driving pulse in the low power mode to be skipped in some frames. According to claim 1,
The touch controller,
And controlling the supply frequency of the low power mode driving pulse to be less than the supply frequency of the normal mode driving pulse. According to claim 1,
The touch controller,
Touch screen driving device characterized in that for sensing the voltage in the low power mode for the Rx lines outside the predetermined range. The method of claim 5,
The touch controller,
And controlling the sensing time in the low power mode region to be smaller than the sensing time in the normal mode region. According to claim 1,
The touch controller,
A device for grouping into at least two Tx lines and supplying a driving pulse in a group unit for Tx lines in the low power mode region outside the predetermined range. A method for driving a touch screen comprising Tx lines and Rx lines, the method comprising:
Supplying a driving pulse to the Tx lines;
Converting sensing voltages of the Rx lines into digital data; And
And generating touch coordinates from the digital data according to a preset touch algorithm,
In the step of supplying the driving pulse,
A certain range is set based on the touch coordinates generated in the previous frame based on the maximum touch coordinate movement value between frames, an area within the predetermined range is set as a normal mode area, and an area outside the predetermined range is a low power mode area. Set, supply a normal mode driving pulse for Tx lines overlapping the normal mode area, and supply a driving pulse of low power mode for Tx lines overlapping the low power mode area and not overlapping the normal mode area, The driving pulse of the low power mode is different from the driving pulse of the normal mode.

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