KR20170052815A

KR20170052815A - Active stylus pen and driving method of the same, and touch sensing system having the active stylus pen

Info

Publication number: KR20170052815A
Application number: KR1020150154701A
Authority: KR
Inventors: 신선경
Original assignee: 엘지디스플레이 주식회사
Priority date: 2015-11-04
Filing date: 2015-11-04
Publication date: 2017-05-15

Abstract

The active stylus pen of the present invention includes: a receiving part for generating a comparator output pulse based on a TSP driving signal received from a touch screen; a validity checking part for analyzing the comparator output pulse with reference to an Rx signal validation condition of a first parameter set among a plurality of preset parameter sets in an Rx mode and checking the validity of the TSP drive signal; and an STx generating part for generating a pen driving signal synchronized with the TSP driving signal with reference to the Tx signal generating condition of the first parameter set in a Tx mode when the TSP driving signal is valid. So, it is possible to minimize noise introduced into the driving signal.

Description

TECHNICAL FIELD [0001] The present invention relates to an active stylus pen, a driving method thereof, and a touch sensing system including an active stylus pen.

The present invention relates to an active stylus pen, and more particularly, to an active stylus pen, a driving method thereof, and a touch sensing system including the active stylus pen.

A user interface (UI) enables a person (user) to easily control various electronic devices as he / she wants. Representative examples of such a user interface include a keypad, a keyboard, a mouse, an on screen display (OSD), a remote controller having infrared communication or radio frequency (RF) communication function, and the like. User interface technology has been developed to enhance the user's sensibility and ease of operation. Recently, the user interface has evolved into a touch UI, a voice recognition UI, a 3D UI, and the like.

The touch UI is essential for portable information devices. The touch UI is implemented by a method of forming a touch screen on the screen of a display device. Such a touch screen can be implemented in a capacitive manner. A touch screen having a capacitive touch sensor has a capacitance (capacitance) according to the input of a touch screen drive signal (hereinafter, referred to as 'TSP drive signal') when a finger or a conductive material touches ), That is, sensing the change of the charge of the touch sensor and sensing the touch input.

The capacitive touch sensor may be implemented as a self capacitance sensor or a mutual capacitance sensor. Each of the electrodes of the capacitance sensor may be connected in a one-to-one relationship with sensor wirings formed along one direction. The mutual capacitance sensor may be formed at the intersection of the sensor wirings orthogonal to each other with the dielectric layer interposed therebetween.

Recently, a stylus pen is used as a human interface device (HID) in smart phones and smart books. The stylus pen has the advantage of being able to input more finely than the finger. There are passive and active stylus pens. The passive stylus pen is difficult to detect the touch position because of the small change in capacitance at the point of contact with the touch screen. On the other hand, since the active stylus pen generates a pen driving signal by itself and outputs the pen driving signal to the contact point with the touch screen, the touch position detection is easier than the passive type, and development thereof is concentrated.

Conventionally, the active stylus pen generates a pen driving signal by simply delaying the TSP driving signal received from the touch screen, so that noise tends to be mixed into the pen driving signal. The pen drive signal is transmitted to the touch screen only during the touch sensor driving period and not transmitted to the touch screen during the display driving period, and the noise distorts the transmission timing of the pen drive signal. When the pen driving signal is transmitted to the touch screen during the display driving period, the image quality is degraded in the display panel including the touch screen.

Noise mixed into the pen drive signal may vary depending on the shape and size of the touch screen. The active stylus pen may be equipped with a noise filter to distinguish effective TSP drive signals from noise, in which case a large number of filters are required to remove various types of noise, thus increasing the hardware size.

In addition, since the conventional active stylus pen is designed only for a single product touch screen, it is difficult to cope with a case in which a signal different from the predetermined TSP driving signal is received.

Accordingly, it is an object of the present invention to provide an active stylus pen, a driving method thereof, and a touch sensing system including an active stylus pen so as to minimize noise incorporated into a pen driving signal without a separate noise filter.

Another object of the present invention is to provide an active stylus pen, a driving method thereof, and a touch sensing system including an active stylus pen, which are applicable not only to a single product but also to a touch screen of various products.

In order to achieve the above object, an active stylus pen of the present invention is an active stylus pen that operates in an Rx mode and a Tx mode based on a touch synchronous signal. The active stylus pen compares a TSP driving signal received from a touch screen with a preset reference voltage, And a validity checking unit for analyzing the comparator output pulse with reference to an Rx signal validity condition of a first parameter set among a plurality of parameter sets predefined in the Rx mode to check the validity of the TSP driving signal An STx generator for generating a pen drive signal synchronized with the TSP drive signal with reference to a Tx signal generation condition of the first parameter set in the Tx mode when the TSP drive signal is valid; Receives the TSP driving signal from the touch screen via a tip, and the Tx De comprises a switching unit for transmitting the pen driving signal to the touch screen through the conductive tip.

The validity checking unit determines that the TSP driving signal is valid when a plurality of consecutive comparator output pulses satisfy an effective period and effective duty corresponding to the Rx signal validity condition.

If the TSP drive signal is not valid, the conductive tip senses the pressure at which the touch screen is depressed.

The active stylus pen of the present invention calculates a period and a duty of the comparator output pulse in a preset phase unit when the pressure is sensed and then outputs a period and a duty when the calculated value is included within a predetermined margin range to the comparator output And an Rx parameter estimating unit that compares the signal estimation condition of each of the parameter sets except for the first parameter set among the parameter sets with the Rx parameter to determine a signal estimation condition most similar to the Rx parameter, Further comprising a parameter selection unit for selecting a parameter set having the first parameter set as a second parameter set and replacing the first parameter set with the selected second parameter set.

If the TSP drive signal is not valid, the STx generator generates a pen drive signal synchronized with the TSP drive signal with reference to the Tx signal generation condition of the second parameter set in the Tx mode.

According to another aspect of the present invention, there is provided a method of driving an active stylus pen operating in an Rx mode and a Tx mode based on a touch synchronous signal, the method comprising: comparing a TSP driving signal received from a touch screen with a predetermined reference voltage to generate a comparator output pulse Analyzing the comparator output pulse with reference to an Rx signal validation condition of a first parameter set among a plurality of predetermined parameter sets in the Rx mode to check the validity of the TSP driving signal; Generating a pen driving signal synchronized with the TSP driving signal with reference to a Tx signal generating condition of the first parameter set in the Tx mode when the signal is valid; Receiving a TSP drive signal and, in the Tx mode, via the conductive tip to the touch screen And transmitting the pen drive signal.

According to another aspect of the present invention, there is provided a touch sensing system including a touch screen, a touch driving device for applying a TSP driving signal to the touch screen based on a touch synchronizing signal and sensing a change in capacitance of the touch screen, The active stylus pen includes a receiving unit for generating a comparator output pulse by comparing a TSP driving signal received from a touch screen with a preset reference voltage, A validity checker for analyzing the comparator output pulse with reference to an Rx signal validation condition of a first parameter set among a plurality of parameter sets preset in the Rx mode to check the validity of the TSP drive signal, The Tx signal generation condition of the first parameter set in the Tx mode is set to An STx generator for generating a pen drive signal synchronized with the TSP drive signal in the Rx mode, and a controller for receiving the TSP drive signal from the touch screen via the conductive tip in the Rx mode, And a switching unit for transmitting the pen driving signal to the screen.

The present invention relates to an active stylus pen that operates in Rx mode and Tx mode based on a touch synchronous signal and discriminates the validity of a TSP driving signal input from a touch screen based on setting information of a default parameter set each time the Rx mode is switched , The pen driving signal synchronized with the TSP driving signal is generated only when the TSP driving signal is valid, thereby minimizing the noise incorporated into the pen driving signal without a separate noise filter.

Further, the present invention further analyzes the TSP drive signal when the TSP drive signal is sensed when the TSP drive signal is not sensed, selects a parameter set having the setup information most similar to the analysis result, After replacing the parameter set, the register information for generating the pen drive signal can be changed in real time according to the setting information of the selected parameter set. Accordingly, the present invention can dramatically improve the product compatibility, for example, the active stylus pen can be applied to a touch screen of various products.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic illustration of a touch sensing system of the present invention.
2 is a view illustrating a display device to which a touch sensing system according to an embodiment of the present invention is applied.
3 is a view showing an example of a touch screen implemented by a mutual capacitance sensor.
4 is a view showing an example of a touch screen implemented with a magnetic capacity sensor.
5 to 7 are views showing a touch driving device according to an embodiment of the present invention.
8 is a view showing a touch sensor driving period and a display driving period which are time-divided according to a touch synchronous signal.
9 is a view showing an internal configuration of an active stylus pen according to the present invention.
10 is a view showing an operation procedure of an active stylus pen according to the present invention.
11 is a view showing an example of a plurality of predetermined parameter sets;
FIGS. 12 and 13 show examples in which a TSP driving signal input to the active stylus is distorted in various noise environments. FIG.
Fig. 14 is a diagram showing a comparator output pulse divided in units of a preset phase; Fig.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Like reference numerals throughout the specification denote substantially identical components. In the following description, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

[Touch Sensing system]

1 schematically shows a touch sensing system of the present invention.

Referring to FIG. 1, the touch sensing system of the present invention includes a display device 10 and an active stylus pen 20.

The display device 10 performs a display function and a touch detection function. The display device 10 is capable of touch detection by the contact of a finger or a conductive object such as the active stylus pen 20, and is equipped with an electrostatic capacitive type touch screen integrally therewith. Here, the touch screen may be configured independently of the display panel for implementing the display, or may be embedded in the pixel array of the display panel. The specific configuration and operation of the display device 10 will be described later with reference to Figs. 2 to 8. Fig.

The active stylus pen 20 operates in the Rx mode and the Tx mode based on the touch synchronous signal. The active stylus pen 20 generates a pen driving signal based on a TSP driving signal received from the touch screen and outputs the pen driving signal to a point of contact with the touch screen to facilitate touch position detection on the touch screen. In particular, the active stylus pen 20 determines the validity of the TSP drive signal input from the touch screen based on the setting information of the default parameter set each time the Rx mode is switched, and synchronizes with the TSP drive signal only when the TSP drive signal is valid A pen drive signal can be generated.

The active stylus pen 20 can sense the pressure when touching the touch screen. The active stylus pen 20 further analyzes the TSP drive signal when the pressure is sensed while the TSP drive signal is in an inactive state, selects a parameter set having setting information most similar to the analysis result, After replacing the default parameter set, the register information for generating the pen drive signal can be changed in real time according to the setting information of the selected parameter set.

The construction and operation of the active stylus pen 20 will be described later with reference to Figs. 8 to 14. Fig.

[Display device]

FIG. 2 shows a display device to which a touch sensing system according to an embodiment of the present invention is applied. FIG. 3 shows an example of a touch screen implemented as a mutual capacitance sensor. 4 shows an example of a touch screen implemented by a magnetic capacity sensor. 5 to 7 show a touch driving apparatus according to an embodiment of the present invention.

2 to 7, the display device 10 of the present invention may be a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP) ), An organic light emitting diode (OLED) display, and an electrophoresis (EPD) display device. In the following embodiments, the display device is implemented as a liquid crystal display device, but the display device of the present invention is not limited to the liquid crystal display device.

The display device 10 comprises a display module and a touch module.

The touch module includes a touch screen (TSP) and a touch driver 18.

The touch screen (TSP) can be implemented in a capacitive manner that senses touch input through a plurality of capacitive sensors. The touch screen TSP includes a plurality of touch sensors having a capacitance. Capacitance can be divided into Self Capacitance and Mutual Capacitance. The electrostatic capacitance can be formed along a single-layer conductor wiring formed in one direction, and mutual capacitance can be formed between two orthogonal conductor wiring.

The touch screen TSP implemented by the mutual capacitive sensor Cm includes Tx electrode lines, Rx electrode lines intersecting the Tx electrode lines, and a plurality of Rx electrode lines at the intersections of the Tx electrode lines and the Rx electrode lines, And the touch sensors Cm formed thereon. The Tx electrode lines are driving signal lines for applying a TSP driving signal to each of the touch sensors Cm to supply electric charges to the touch sensors. The Rx electrode lines are sensor wirings connected to the touch sensors Cm to supply the charges of the touch sensors to the touch driver 18. [ In the mutual capacitance sensing method, a driving signal is applied to the Tx electrode through the Tx electrode line to supply electric charge to the touch sensor (Cm), and the electric charge of the touch sensor (Cm) By sensing the capacitance change, the touch input can be detected.

The touch screen TSP implemented by the capacitance sensor Cs may be connected in a one-to-one relationship with the sensor wires 32 formed along one direction of the touch electrodes 31 as shown in FIG. The capacitance sensor Cs includes a capacitance formed in each of the electrodes 31. [ In the capacitance sensing method, when a TSP driving signal is applied to the electrode 31 through the sensor wiring 32, the charge Q is accumulated in the touch sensor Cs. At this time, when a finger or a conductive object contacts the electrode 31, the parasitic capacitance Cf is further connected to the capacitance sensor Cs to change the total capacitance value. Accordingly, the capacitance value between the finger-touched sensor and the non-touched sensor can be changed to determine whether the finger is touched or not.

The touch screen TSP may be bonded onto the upper polarizer plate of the display panel DIS or between the upper polarizer plate of the display panel DIS and the upper substrate. In addition, the touch sensors Cm or Cs of the touch screen TSP may be embedded in the pixel array of the display panel DIS. In order to embed the touch sensors Cm or Cs into the pixel array, the common electrode of the pixels may be divided into a plurality of segments. In this case, the touch sensors Cm or Cs may be implemented as divided common electrodes. One common electrode segment may be connected in common to a plurality of pixels and form one touch sensor. A common voltage is applied to the common electrode of the pixels during the display driving period, and a TSP driving signal is applied during the touch sensor driving period.

The touch driver 18 senses the amount of change in the charge of the touch sensor before and after touching to judge whether or not a conductive substance such as a finger (or a stylus pen) touches and its position.

The touch-driving device 18 of the present invention can be implemented as an IC (Integrate Circuit) package as shown in FIGS.

Referring to FIG. 5, the touch driver 18 includes a driver IC (DIC) and a touch IC (TIC).

The driver IC DIC includes a touch sensor channel unit 100, a Vcom buffer 110, a switch array 120, a timing control signal generating unit 130, a multiplexer (MUX) 140, 150).

The touch sensor channel unit 100 is connected to the electrodes of the touch sensors through sensor wirings (or Rx electrode lines), and is connected to the Vcom buffer 110 and the multiplexer 140 through the switch array 120. The multiplexer 140 connects the sensor wires to the touch IC (TIC). In the case of the 1: 3 multiplexer, the multiplexer 140 reduces the number of channels of the touch IC (TIC) by sequentially connecting one channel of the touch IC (TIC) to the three sensor wirings in a time division manner. The multiplexer 140 sequentially selects the sensor wirings to be connected to the channel of the touch IC (TIC) in response to the MUX control signals MUX C1 to C3. The multiplexer 140 is connected to the channels of the touch IC (TIC) through the touch lines.

The Vcom buffer 110 outputs the common voltage Vcom of the pixel. The switch array 120 supplies the common voltage Vcom from the Vcom buffer 110 to the touch sensor channel unit 100 under the control of the timing control signal generation unit 130 during the display driving period. The switch array 120 connects the sensor wires to the touch IC (TIC) under the control of the timing control signal generator 130 during the touch sensor driving period.

The timing control signal generator 130 generates timing control signals for controlling the operation timings of the display driving circuit and the touch IC (TIC). The display driving circuit includes a data driving circuit (12) and a gate driving circuit (14) for writing data of an input image to a pixel. The data driving circuit 12 generates a data voltage and supplies it to the data lines D1 to Dm of the display panel DIS. The data driving circuit 12 can be integrated in the driver IC (DIC). The gate drive circuit 14 sequentially supplies a gate pulse (or a scan pulse) synchronized with the data voltage to the gate lines G1 to Gn of the display panel DIS. The gate drive circuit 14 may be disposed together with the pixels on the substrate of the display panel DIS.

The timing control signal generator 130 is substantially the same as the timing control signal generator in the timing controller 16 shown in FIG. The timing control signal generator 130 drives the display driving circuit during the display driving period and drives the touch IC (TIC) during the touch sensor driving period.

The timing control signal generating unit 130 generates a touch synchronizing signal Tsync that defines the display driving period DP and the touch sensor driving period TP as shown in Fig. 8 and synchronizes the display driving circuit and the touch IC (TIC) . The display drive circuit writes data to the pixels during the first level period of the touch synchronous signal Tsync. The touch IC (TIC) senses the touch input by driving the touch sensors in response to the second level of the touch synchronizing signal Tsync. The first level of the touch synchronous signal Tsync may be a low level, the second level may be a high level, or vice versa.

The touch IC (TIC) is connected to a driving power source (not shown) to receive driving power. The touch IC TIC generates a TSP driving signal in response to the second level of the touch synchronizing signal Tsync and applies it to the touch sensors of the touch screen TSP. The TSP driving signal may be generated in various forms such as a square wave type pulse, a sinusoidal wave, and a triangular wave, but it is preferably implemented as a square wave. The TSP driving signal may be applied N times to each of the touch sensors so that the electric charge can be accumulated in the integrator of the touch IC (TIC) more than N (N is a natural number of 2 or more) times.

The noise may be increased in the touch sensor signal according to the change of the input image data. The DTX compensator 150 analyzes the input image data, removes noise components from the touch raw data according to the gradation change of the input image, and transmits the same to the touch IC (TIC). DTX stands for Display and Touch crosstalk. The contents of the DTX compensation unit 150 are described in detail in the patent application No. 10-2012-0149028 (filed December 19, 2012), which is filed by the present applicant. In the case of a system in which the noise of the touch sensor does not change sensitively according to the data change of the input image, the DTX compensation unit 150 is not necessary and can be omitted. In FIG. 5, DTX DATA is the output data of the DTX compensator 150.

The touch IC TIC drives the multiplexer 140 during the touch sensor driving period TP in response to the touch synchronizing signal Tsync from the timing control signal generating section 130 to generate a touch signal And receives the charge of the sensor. In FIG. 5, the MUXs C1 to C3 are signals for selecting the channel of the multiplexer.

The touch IC (TIC) detects the amount of charge change before and after the touch input from the touch sensor signal, compares the amount of charge change with a predetermined threshold value, and determines the position of the touch sensor having the charge variation amount equal to or larger than the threshold value as the touch input area. The touch IC (TIC) calculates coordinates for each touch input and transmits touch data (TDATA (XY)) including touch input coordinate information to the external host system. The touch IC (TIC) includes an amplifier for amplifying the charge of the touch sensor, an integrator for accumulating the charge received from the touch sensor, an ADC (Analog to Digital Converter) for converting the voltage of the integrator into digital data, and an arithmetic logic section. The arithmetic logic unit compares the touch raw data output from the ADC with a threshold value, and executes a touch recognition algorithm that determines a touch input and calculates coordinates based on the comparison result.

The driver IC (DIC) and the touch IC (TIC) can transmit and receive signals through the SPI (Serial Peripheral Interface) interface.

Referring to FIG. 6, the touch driver 18 includes a driver IC (DIC) and an MCU (Micro Controller Unit).

The driver IC DIC includes a touch sensor channel unit 100, a Vcom buffer 110, a switch array 120, a first timing control signal generating unit 130, a multiplexer 140, a DTX compensating unit 150, Unit 160, a second timing control signal generator 170, and a memory 180. This embodiment differs from the embodiment of FIG. 5 in that the sensing unit 160 and the second timing control generator 170 are integrated in the driver IC (DIC). The first timing control generator 130 is substantially the same as that of FIG. Therefore, the first timing control generator 130 generates timing control signals for controlling the operation timing of the display driving circuit and the touch IC (TIC).

The sensing unit 160 includes an amplifier for amplifying the charge of the touch sensor, an integrator for accumulating the charge received from the touch sensor, and an ADC for converting the voltage of the integrator into digital data. Touch raw data (TDATA) output from the ADC is sent to the MCU. The second timing control generator 170 generates a timing control signal for controlling the operation timing of the multiplexer 140, the sensing unit 160, a clock, and the like. The DTX compensation section 150 in the driver IC (DIC) may be omitted. The memory 180 temporarily stores data (TDATA) under the control of the second timing control generator 170.

Driver IC (DIC) and MCU can send and receive signals through SPI (Serial Peripheral Interface) interface. The MCU compares the data (TDATA) with a threshold value with a touch, executes a touch recognition algorithm to determine the touch input according to the result of the comparison and to calculate coordinates.

Referring to FIG. 7, the touch driver 18 includes a driver IC (DIC) and a memory (Memory, MEM).

The driver IC DIC includes a touch sensor channel unit 100, a Vcom buffer 110, a switch array 120, a first timing control signal generating unit 130, a multiplexer 140, a DTX compensating unit 150, Unit 160, a second timing control signal generator 170, a memory 180, and an MCU 190. This embodiment differs from the above-described embodiment of FIG. 6 in that the MCU 190 is integrated in a driver IC (DIC). The MCU 18 compares the data TDATA with a threshold value by touching, executes a touch recognition algorithm for determining a touch input according to the comparison result, and calculating coordinates.

The memory MEM stores a register setting value related to the timing information necessary for the operation of the display driving circuit and the sensing unit 160. [ The register set value is loaded from the memory MEM to the first timing control signal generator 130 and the second timing control signal generator 170 when the power of the display device is turned on. The first timing control signal generating unit 130 and the second timing control signal generating unit 170 generate timing control signals for controlling the display driving circuit and the sensing unit 160 based on the register setting values read from the memory do. It is possible to cope with the model change by changing the register setting value of the memory MEM without structural modification of the driving apparatus.

The display module may include a display panel (DIS), a display driving circuit (12, 14, 16), and a host system (19).

The display panel DIS includes a liquid crystal layer formed between two substrates. The pixel array of the display panel DIS includes pixels formed in the pixel region defined by the data lines (D1 to Dm, m is a positive integer) and the gate lines (G1 to Gn, n is a positive integer) . Each of the pixels includes a TFT (Thin Film Transistor) formed at intersections of the data lines D1 to Dm and the gate lines G1 to Gn, a pixel electrode for charging a data voltage, A storage capacitor (Cst) for maintaining a voltage, and the like.

A black matrix, a color filter, and the like may be formed on the upper substrate of the display panel DIS. The lower substrate of the display panel DIS may be implemented with a COT (Color Filter On TFT) structure. In this case, the black matrix and the color filter can be formed on the lower substrate of the display panel DIS. The common electrode to which the common voltage is supplied may be formed on the upper substrate or the lower substrate of the display panel DIS. On the upper substrate and the lower substrate of the display panel DIS, a polarizing plate is attached, and an alignment film for forming a pre-tilt angle of the liquid crystal on the inner surface in contact with the liquid crystal is formed. A column spacer for maintaining a cell gap of the liquid crystal cell is formed between the upper substrate and the lower substrate of the display panel DIS.

A backlight unit may be disposed below the rear surface of the display panel DIS. The backlight unit is implemented as an edge type or direct type backlight unit, and irradiates the display panel (DIS) with light. The display panel DIS may be implemented in any known liquid crystal mode such as TN (Twisted Nematic) mode, VA (Vertical Alignment) mode, IPS (In Plane Switching) mode and FFS (Fringe Field Switching) mode.

The display driving circuit includes a data driving circuit 12, a gate driving circuit 14, and a timing controller 16, and writes video data of an input image to pixels of the display panel DIS. The data driving circuit 12 converts the digital video data RGB input from the timing controller 16 into an analog positive / negative gamma compensation voltage to output a data voltage. The data voltage output from the data driving circuit 12 is supplied to the data lines D1 to Dm. The gate drive circuit 14 sequentially supplies a gate pulse (or a scan pulse) synchronized with the data voltage to the gate lines G1 to Gn to select the pixel line of the display panel DIS to which the data voltage is written.

The timing controller 16 inputs timing signals such as a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a data enable signal DE and a main clock MCLK input from the host system 19 And synchronizes the operation timings of the data driving circuit 12 and the gate driving circuit 14 with each other. The scan timing control signal includes a gate start pulse (GSP), a gate shift clock, a gate output enable signal (GOE), and the like. The data timing control signal includes a source sampling clock (SSC), a polarity control signal (Polarity), a source output enable signal (SOE), and the like.

The host system 19 transmits the timing signals Vsync, Hsync, DE and MCLK to the timing controller 16 together with the digital video data RGB and outputs the touch coordinate information XY ). &Lt; / RTI >

On the other hand, the touch synchronous signal TEN of FIG. 8 may be generated in the host system 19. During the display driving period DP, the data driving circuit 12 supplies the data voltages to the data lines D1 to Dm under the control of the timing controller 16, and the gate driving circuit 14 supplies the data voltages to the timing controller 16. [ A gate pulse synchronized with the data voltage is sequentially supplied to the gate lines G1 to Gn under the control of the control circuit. On the other hand, during the display driving period DP, the touch driving device 18 stops operating.

During the touch sensor drive period TP, the touch driver 18 applies a TSP drive signal to the touch sensors of the touch screen TSP. Meanwhile, during the touch sensor driving period TP, the display driving circuits 12, 14, and 16 are turned on in order to minimize the parasitic capacitance between the signal lines D1 to Dm, G1 to Gn connected to the pixels and the touch sensors It is possible to supply an AC signal having the same amplitude and the same phase as the TSP drive signal to the signal lines D1 to Dm and G1 to Gn. In this case, the display noise mixed into the touch sensing signal is remarkably reduced, and the accuracy of the touch sensing is increased.

[ Stylus pen]

8 shows a touch sensor driving period and a display driving period which are time-divided according to a touch synchronous signal. 9 shows an internal configuration of an active stylus pen according to the present invention.

8 and 9, the active stylus pen 20 of the present invention includes a conductive tip 201 and a conductive tip 201 connected to the conductive tip 201 in order to minimize noise incorporated into the pen driving signal without a separate noise filter. A reception unit 203, a validity checking unit 204, an STx generating unit 205, and a transmitting unit 206. The switching unit 202,

The conductive tip 201 is made of a conductive material such as metal and serves as a receiving electrode and a transmitting electrode. When the conductive tip 201 is contacted on the touch screen TSP of the display device 20, the conductive tip 201 is coupled to the touch screen TSP at the contact point. The conductive tip 201 receives the TSP driving signal TS from the touch screen TSP at the point of contact and sends the pen driving signal PS generated inside the active stylus pen 20 to the touch screen TSP). Since the conductive tip 201 serves also as a receiving electrode and a transmitting electrode, the structure of the active stylus 20 is simplified.

The switching unit 202 switches the reception timing of the TSP driving signal TS and the transmission of the pen driving signal PS when the conductive tip 201 contacts the touch screen TSP of the display device 20. [ Timing is separated in time. The switching unit 202 transmits the TSP driving signal TS inputted from the touch screen TSP to the receiving unit 203 via the conductive tip 201 in the Rx mode and generates the TSP driving signal TS generated by the STx generating unit 205 in the Tx mode To the touch screen (TSP) through the conductive tip (201).

The receiving unit 203 may include at least one amplifier to amplify the TSP driving signal Ts input through the switching unit 202. [ The receiving unit 203 also includes a comparator for comparing the amplified signal from the amplifier with a preset reference voltage, and generating a comparator output pulse SRx as a result of the comparison.

After receiving the comparator output pulse SRx from the receiving unit 203, the validation checking unit 204 compares the Rx signal validity condition of the first parameter set (the default parameter set) (SRx) is analyzed to check the validity of the TSP driving signal (TS). Specifically, the validity checker 204 compares the validity period (PE) of the N (N is a positive integer equal to or greater than two) consecutive comparator output pulses SRx, which correspond to the Rx signal validity condition of the first parameter set, ) And the effective duty DT are satisfied, it is possible to determine that the TSP driving signal TS is valid.

When the validity checker 204 determines that the TSP drive signal TS is valid, the STx generator 205 converts the Tx signal into a Tx signal by referring to the Tx signal generation condition of the first parameter set The pen drive signal PS synchronized with the pen drive signal PS is generated. In other words, the STx generating unit 205 synchronizes the TSP driving signal TS with the Tx signal generating conditions (cycle, duty, number, etc.) of the first parameter set loaded into the register after a certain time delay at the Tx mode switching time The pen drive signal PS can be generated.

The active stylus pen 20 of the present invention is not limited to a single product but can be applied to a touch screen of various products in order to improve the compatibility of the product. In addition to the components 201, 202, 203, 204, 205, ), An Rx parameter evaluation unit 208, and a parameter selection unit 209. [

The pressure sensing unit 207 senses the pressure at which the conductive tip 201 is pressed on the touch screen TSP and supplies the pressure sensing information to the Rx parameter evaluation unit 208. [

When the validity checker 204 determines that the TSP drive signal TS is not valid, the Rx parameter evaluator 208, based on the pressure sensing information from the pressure-sensing sensor 207, The cycle and the duty of the output pulse SRx are calculated in units of a predetermined phase as shown in FIG. 14, and the cycle and the duty when the calculated value is included in the predetermined margin range are set to Rx Parameter.

The parameter selecting unit 209 compares the signal estimation condition of each of the remaining parameter sets except for the first parameter set among the predetermined parameter sets with the Rx parameter to obtain a parameter set having the signal estimation condition most similar to the Rx parameter Is selected as the second parameter set, and the first parameter set is replaced with the second parameter set. In this case, the STx generating unit 205 generates the pen driving signal STx synchronized with the TSP driving signal TS, with reference to the Tx signal generating condition of the second parameter set in the Tx mode.

10 shows the operation procedure of the active stylus pen according to the present invention. 11 shows an example of a plurality of predetermined parameter sets. Figs. 12 and 13 show examples in which the TSP driving signal inputted to the active stylus pen is distorted in various noise environments. 14 shows that the comparator output pulses are divided by a predetermined phase unit.

The operation procedure of the active stylus pen according to the present invention will be described with reference to FIGS. 10 to 14. FIG.

The active stylus pen according to the present invention (hereinafter, referred to as the present invention) has a plurality of predetermined parameter sets as shown in FIG. The parameter sets are pre-stored in the memory corresponding individually to the models of the touch screen (TSP). For example, in FIG. 11, parameter set 1 may correspond to a 5.5 inch touch screen, and parameter set 2 may correspond to a 15.6 inch touch screen.

The parameter sets include characteristic parameters of the Tx or Rx signal. The characteristic parameters include an SRx validation condition, a signal estimation condition, and an STx generation condition.

The SRx validity condition (Rx signal validity condition) is for checking the validity of the TSP drive signal (TS), and includes Rx pulse number and Rx pulse validation parameter. Rx pulse validation parameters include Rx pulse low / high width and Rx pulse low / high skip width. Here, the Rx pulse low / high width represents the effective period and effective duty of the Rx pulse.

The signal estimation condition is for changing the parameter set when the validity of the TSP driving signal (TS) is not satisfied. The signal estimation condition includes a low / high level for the high width of the measurement pulse and a low / high level for the low width of the measurement pulse .

The STx generation condition (Tx signal generation condition) is for generating a pen drive signal STx synchronized with the TSP drive signal TS and includes a Tx pulse number, a Tx pulse start time delay value, a Tx pulse low / And the like.

The present invention selects either one of the parameter sets as a default parameter set and then compares the TSP drive signal TS received from the touch screen TSP with a predetermined reference voltage to generate a comparator output pulse SRx, Mode, the comparator output pulse SRx is analyzed with reference to the SRx validity condition of the default parameter set to check the validity of the TSP driving signal TS (S1, S2). When the TSP drive signal TS is valid, the present invention generates a pen drive signal STx synchronized with the TSP drive signal TS with reference to the STx generation condition of the default parameter set in the Tx mode (S3 and S4) .

For example, the present invention selects parameter set 1 as a default parameter set and monitors whether the three consecutive pulse signals of the comparator output pulse SRx satisfy the SRx validity condition of parameter set 1, as in Fig. In this case, according to the present invention, when the row / high width of each of the three consecutive pulse signals satisfies the 100 占 margin value, it is determined that the TSP driving signal TS is valid, (STx).

On the other hand, when the TSP drive signal TS is not valid, the present invention performs the Rx pulse evaluation process and newly selects the most suitable parameter set among the parameter sets based on the result. The default parameter set is changed to a new parameter set by the Rx pulse evaluation process. This Rx pulse evaluation process starts at the time when the pressure is present.

The Rx pulse evaluation process is performed to distinguish the noise from the normal signal at the comparator output signal SRx and to estimate the period and duty of the comparator output signal SRx through the high / low interval of the steady signal. The TSP drive signal (TS) input to the active stylus pen may be distorted in various noise environments. The noise is relatively large in the hovering state of the stylus pen as shown in Fig. 12, and relatively small in the contact state of the stylus pen as shown in Fig.

The Rx pulse evaluation process divides the input comparator output signal SRx into phase units (Phase 0 to 2) as shown in FIG. 14 and then outputs the signal amplitude (high range width or low range Width). Then, the Rx pulse evaluation process compares the calculated values in units of phases. The phases to be compared may be adjacent to each other or may be spaced in time. The Rx pulse evaluation process determines that there is no noise when the signal difference between the phases falls within the predetermined margin range, and selects the corresponding phase average value as the Rx parameter of the comparator output pulse SRx. Then, the Rx pulse evaluation process compares the selected Rx parameter with the signal estimation condition stored in each parameter set, and selects a parameter set having a signal estimation condition most similar to the Rx parameter as a new parameter set.

In other words, the present invention senses the pressure at which the conductive tip is depressed on the touch screen when the TSP drive signal (TS) is not valid, and uses the Rx pulse evaluation process, The cycle and duty of the comparator output pulse SRx are calculated by the preset phase unit (Phase 0 to 2), and the cycle and duty when the calculated value is included in the predetermined margin range are set as the Rx parameter of the comparator output pulse SRx I decide. The present invention compares the signal estimation condition of each of the remaining parameter sets except for the default parameter set among the parameter sets with the Rx parameter and selects a parameter set having the signal estimation condition most similar to the Rx parameter as a new parameter set , Thereby replacing the default parameter set with a new parameter set (S4, S5, S6, S7).

For example, under the determination that the TSP drive signal (TS) is not valid if the row / high width of each of the three consecutive pulse signals in Figure 11 does not satisfy the 100 占 margin value, the present invention performs the Rx pulse evaluation process do. If the Rx parameter calculated through the Rx pulse evaluation process belongs to the signal estimation condition of parameter set 2 as 190, 210, the present invention replaces the default parameter set with parameter set 2. Then, the present invention generates the pen drive signal STx in accordance with the Tx signal generation condition of the parameter set 2.

As described above, according to the present invention, in the active stylus pen operating in the Rx mode and the Tx mode on the basis of the touch synchronous signal, each time the Rx mode is switched, the TSP driving signal And generates a pen drive signal synchronized with the TSP drive signal only when the TSP drive signal is effective, thereby minimizing the noise incorporated into the pen drive signal without a separate noise filter.

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 invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

10: display device 18: touch drive device
20: Stylus Pen 201: Conductive tip
202: switching unit 203:
204: validity checker 205: STx generator
206: Transmitting section 207:
208: Rx parameter evaluation unit 209: Parameter selection unit

Claims

An active stylus pen operating in an Rx mode and a Tx mode based on a touch synchronous signal,
A receiver for comparing the TSP drive signal received from the touch screen with a predetermined reference voltage to generate a comparator output pulse;
A validity checker for analyzing the comparator output pulse with reference to an Rx signal validation condition of a first parameter set among a plurality of parameter sets preset in the Rx mode to check validity of the TSP drive signal;
An STx generating unit for generating a pen driving signal synchronized with the TSP driving signal with reference to a Tx signal generating condition of the first parameter set in the Tx mode when the TSP driving signal is valid; And
And a switching unit for receiving the TSP drive signal from the touch screen through the conductive tip in the Rx mode and transmitting the pen drive signal to the touch screen via the conductive tip in the Tx mode.

The method according to claim 1,
Wherein the validity checking unit determines that the TSP driving signal is valid when a plurality of consecutive comparator output pulses satisfy an effective period and an effective duty corresponding to the Rx signal validity condition.

3. The method of claim 2,
A pressure-sensing unit configured to sense a pressure at which the conductive tip is pressed on the touch screen when the TSP drive signal is not valid;
The duty cycle of the comparator output pulse is calculated in units of a preset phase and the duty cycle of the output pulse is set to Rx parameter of the comparator output pulse when the pressure is detected within a predetermined margin range, A parameter evaluation unit; And
Compares the signal estimation condition of each of the parameter sets except for the first parameter set among the parameter sets with the Rx parameter, selects a parameter set having a signal estimation condition most similar to the Rx parameter as a second parameter set And a parameter selection unit that replaces the first parameter set with the selected second parameter set.

The method of claim 3,
Wherein the STx generator generates a pen driving signal synchronized with the TSP driving signal with reference to a Tx signal generating condition of the second parameter set in the Tx mode when the TSP driving signal is invalid.

A method of driving an active stylus pen operating in an Rx mode and a Tx mode based on a touch synchronous signal,
Comparing the TSP drive signal received from the touch screen with a predetermined reference voltage to generate a comparator output pulse;
Analyzing the comparator output pulse with reference to an Rx signal validation condition of a first parameter set among a plurality of predetermined parameter sets in the Rx mode to check validity of the TSP driving signal;
Generating a pen drive signal synchronized with the TSP drive signal with reference to a Tx signal generation condition of the first parameter set in the Tx mode when the TSP drive signal is valid; And
Receiving the TSP drive signal from the touch screen via a conductive tip in the Rx mode and transmitting the pen drive signal to the touch screen via the conductive tip in the Tx mode.

6. The method of claim 5,
Wherein the validity checking step determines that the TSP driving signal is valid when a plurality of successive comparator output pulses satisfy an effective period and an effective duty corresponding to the Rx signal validity condition.

The method according to claim 6,
Sensing a pressure at which the conductive tip is depressed on the touch screen if the TSP drive signal is not valid;
Calculating a period and a duty of the comparator output pulse in a predetermined phase unit when the pressure is sensed and then setting a period and a duty when the calculated value is within a predetermined margin range to an Rx parameter of the comparator output pulse ; And
Comparing a signal estimation condition of each of the parameter sets other than the first parameter set among the parameter sets with the Rx parameter and selecting a parameter set having a signal estimation condition most similar to the RX parameter as a second parameter set And replacing the first set of parameters with the selected second set of parameters.

8. The method of claim 7,
Generating a pen drive signal synchronized with the TSP drive signal when the TSP drive signal is not valid, the step of generating a pen drive signal synchronized with the TSP drive signal is performed by referring to a Tx signal generation condition of the second parameter set in the Tx mode, A driving method of an active stylus pen for generating a driving signal.

touch screen;
A touch driver that applies a TSP driving signal to the touch screen based on a touch synchronous signal and senses a capacitance change of the touch screen; And
And an active stylus pen operating in an Rx mode and a Tx mode based on the touch synchronous signal Tsync,
The active stylus pen includes:
A receiver for comparing the TSP drive signal received from the touch screen with a predetermined reference voltage to generate a comparator output pulse;
A validity checker for analyzing the comparator output pulse with reference to an Rx signal validation condition of a first parameter set among a plurality of parameter sets preset in the Rx mode to check validity of the TSP drive signal;
An STx generating unit for generating a pen driving signal synchronized with the TSP driving signal with reference to a Tx signal generating condition of the first parameter set in the Tx mode when the TSP driving signal is valid; And
A switch for receiving the TSP drive signal from the touch screen via the conductive tip in the Rx mode and transmitting the pen drive signal to the touch screen via the conductive tip in the Tx mode.

10. The method of claim 9,
Wherein the validity checking unit determines that the TSP driving signal is valid when a plurality of consecutive comparator output pulses satisfy an effective period and an effective duty corresponding to the Rx signal validity condition.

11. The method of claim 10,
A pressure-sensing unit configured to sense a pressure at which the conductive tip is pressed on the touch screen when the TSP drive signal is not valid;
The duty cycle of the comparator output pulse is calculated in units of a preset phase and the duty cycle of the output pulse is set to Rx parameter of the comparator output pulse when the pressure is detected within a predetermined margin range, A parameter evaluation unit; And
Compares the signal estimation condition of each of the parameter sets except for the first parameter set among the parameter sets with the Rx parameter, selects a parameter set having a signal estimation condition most similar to the Rx parameter as a second parameter set And a parameter selection unit for replacing the first parameter set with the selected second parameter set.

12. The method of claim 11,
When the TSP drive signal is invalid, the STx generator generates a pen drive signal synchronized with the TSP drive signal with reference to a Tx signal generation condition of the second parameter set in the Tx mode.