KR20170036940A - Active touch pen and touch sensing system and driving method of the same - Google Patents

Abstract

A touch sensing system according to the present invention includes: a touch screen; a touch driving device applying a touch driving signal to the touch screen, and calculating a plurality of touch input coordinates by sensing changes in capacitance of the touch screen; and an active touch pen for transmitting a pen driving signal synchronized with the touch driving signal through a tip, sensing the pressure applied in the vertical direction of the tip when the tip contacts the touch screen to generate pressure information, and providing the pressure information to the touch driving device. The touch driving device includes a touch input calculating unit, a horizontal angle calculating unit, an error length calculating unit, and a touch input correcting unit. The touch input calculating unit calculates pen touch coordinates and palm peak coordinates according to the number labeled in the touch input coordinates. The horizontal angle calculating unit calculates the palm peak coordinate direction as the tip horizontal vector in the pen touch coordinates, and calculates the horizontal angle information formed by a reference axis and the tip horizontal vector in a touch coordinate system. The error length calculating unit calculates the error length of the pen touch coordinates based on the pressure information. The touch input correcting unit calculates touch correction coordinates compensated with the error length in the direction of the negative vector in the direction opposite to the tip horizontal vector in the pen touch coordinates.

Description

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

The present invention relates to a touch sensing system, and more particularly, to a touch sensing system capable of touch input through an active touch pen and a driving method thereof.

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. When a finger or a conductive material touches (or comes close to) the touch sensor, the touch screen having the capacitive touch sensor senses a change in capacitance due to the input of the touch screen drive signal, that is, Thereby detecting 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.

In recent years, not only a finger but also a stylus pen has been widely used as a human interface device (HID) in smart phones and smart books. The touch pen has a passive type and an active type. In the passive type, it is difficult to detect the touch position because the capacitance change is small at the contact point with the touch screen. The active type generates the pen drive signal itself and outputs it to the contact point with the touch screen, so it is easier to detect the touch position than the passive type.

The touch pen has a merit that it is possible to input a more detailed input than a finger, so that a touch input is required even in a small touch screen device, and a writing function can be performed. However, because the touch pen is significantly less accurate than an analog writing instrument, the accuracy of the touch pen is still insufficient to meet the needs of users.

Accordingly, the present invention provides a touch pen capable of performing more precise touch input with a touch pen, a touch sensing system including the touch pen, and a driving method thereof.

According to an aspect of the present invention, there is provided a touch sensing system including a touch screen, a touch driving device for applying a touch driving signal to a touch screen, sensing a change in capacitance of the touch screen to calculate a plurality of touch input coordinates, An active touch pen for transmitting a pen drive signal synchronized with the signal through the tip and sensing the pressure applied in the vertical direction of the tip when the tip contacts the touch screen to generate pressure information and providing pressure information to the touch driver; . The touch driver includes a touch input calculating unit, a horizontal angle calculating unit, an error length calculating unit, and a touch input correcting unit. The touch input calculating unit calculates the pen touch coordinate and the palm peak coordinate according to the number labeled in the plurality of touch input coordinates. The horizontal angle calculating unit calculates the palm peak coordinate direction as the tip horizontal vector in the pen touch coordinates, and calculates the horizontal angle information formed by the reference axis and the tip horizontal vector in the touch coordinate system. The error length calculating unit calculates the error length of the pen touch coordinates based on the pressure information. The touch input correction unit calculates the touch correction coordinate that compensates the error length in the direction of the tone vector in the direction opposite to the tip horizontal vector in the pen touch coordinates.

According to the present invention, an error length in which a tip is tilted is calculated based on vertical information applied to a tip, a horizontal angle in a direction in which the pen is oriented is calculated based on an area in contact with a user's hand, Correct input coordinates. Therefore, it is possible to more accurately calculate the point where the actual user touches the tip.

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 that one frame is time-divided into a display driving period and a touch sensor driving period.
9 to 12 are views showing a configuration of an active touch pen according to the present invention.
13 illustrates a touch screen drive signal and a touch pen drive signal.
14 is a flowchart showing the operation of the touch correcting unit;
Figs. 15 and 16 are diagrams for calculating touch input coordinates and palm coordinates. Fig.
17 is a schematic diagram showing a touch input correction method.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Like reference numerals throughout the specification denote substantially identical components. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description, a detailed description of known technologies or configurations related to the present invention will be omitted when it is determined that the gist of the present invention may be unnecessarily obscured. In addition, the component names used in the following description may be selected in consideration of easiness of specification, and may be different from the parts names of actual products.

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 touch pen 20.

The display device 10 performs a display function and a touch detection function. The display device 10 is capable of performing touch detection by the contact of a finger or a conductive object such as the active touch pen 20, and is provided with a touch screen of an electrostatic capacitive type 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 touch pen 20 generates a pen driving signal based on a touch screen 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. The active touch pen 20 acquires vertical pressure information and pressure information when the tip contacts the touch screen. The vertical pressure information is used in the process of correcting the touch input coordinates. The pressure information is used to modulate the pen drive signal.

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 touch screen 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 a Tx electrode through a Tx electrode line to supply a charge to a touch sensor (Cm), and a voltage is applied to the touch sensor (Cm) through an Rx electrode and an Rx electrode line By sensing the change in capacitance, 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 touch screen 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 determined by touching.

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.

The touch driver 18 senses the amount of change in the charge of the touch sensor before and after the touch to judge whether or not a conductive substance such as a finger (or a touch pen) is touched 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 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 GL1 to GLn 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 enable signal TEN defining the display driving period T1 and the touch sensor driving period T2 as shown in FIG. Synchronize. The display driving circuit writes data to the pixels during the first level period of the touch enable signal TEN. The touch IC (TIC) senses the touch input by driving the touch sensors in response to the second level of the touch enable signal TEN. The first level of the touch enable signal TEN may be a low level, the second level may be a high level, and 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 touch screen driving signal in response to the second level of the touch enable signal TEN and applies it to the touch sensors of the touch screen TSP. The touch screen 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 touch screen driving signal may be applied to each of the touch sensors N times so that electric charges 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 T2 in response to the touch enable signal TEN from the timing control signal generating unit 130 and outputs the signal through the multiplexer 140 and the sensor wirings And receives the charge of the touch 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.

The host system 19 refers to a system body of an electronic apparatus to which the display apparatus 10 of the present invention is applicable. The host system 19 may be any one of a phone system, a television system, a set top box, a navigation system, a DVD player, a Blu-ray player, a personal computer (PC), and a home theater system. The host system 19 transmits the input image data RGB to the driver IC DIC and receives the touch input data TDATA XY from the touch IC TIC and outputs an application associated with the touch input, .

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 175. [ 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. Accordingly, 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 175, 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 190 compares the data TDATA with the threshold temporarily stored in the memory 175 and executes a touch recognition algorithm for determining the touch input and calculating the coordinates according to the comparison result.

The memory 175 stores a register setting value related to the timing information required 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 16 and the second timing control signal generator 170 when the power of the display device is turned on. The first timing control signal generator 16 and the second timing control signal generator 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 ). ≪ / RTI >

On the other hand, the touch enable signal TEN may be generated in the host system 19. During the display driving period T1, the data driving circuit 12 supplies the data voltage 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 T1, the touch driving device 18 stops operating.

During the touch sensor driving period T2, the touch driving device 18 applies a touch screen driving signal to the touch sensors of the touch screen TSP. Meanwhile, during the touch sensor driving period T2, 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 touch screen driving 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.

FIGS. 9 and 10 are perspective views of an active type touch pen according to the present invention, and FIGS. 11 and 12 are views showing the internal structure of the active type touch pen.

9 to 12, the active touch pen of the present invention will be described as follows. The active touch pen 20 includes a housing 280 and a tip 210 projecting from one end of the housing 280. A vertical pressure sensing portion 216 is disposed around the tip 210 and a switching portion 220 is disposed at an end of the tip 210 in the housing 280. Inside the housing, a receiving unit 230 for receiving a touch screen driving signal input from the tip 210 through the switching unit 220, and a controller 230 for synchronizing the pressure information based on the touch screen driving signal from the receiving unit 230 A driving unit 240 for level-shifting the modulating pen driving signal generated by the signal processing unit 250 and then supplying the modulating pen driving signal to the tip 210 through the switching unit 220, A power supply unit 260 for generating driving power required for the operation, and an input / output interface 270.

The tip 210 is made of a conductive material such as metal and serves as a receiving electrode and a transmitting electrode. When the tip 210 is contacted on the touch screen TSP of the display, the tip 210 is coupled to the touch screen TSP at that point of contact. The tip 210 receives the touch screen drive signal from the touch screen TSP at the contact point and then transmits the modulation pen drive signal generated inside the active touch pen 20 to the contact of the touch screen TSP Point.

The vertical pressure sensing unit 216 of the tip 210 senses a pressure F1 applied perpendicularly to the longitudinal direction of the tip 210 when the tip 210 contacts the touch screen TSP.

The pressure sensing unit 217 senses a pressure F2 applied in the longitudinal direction of the tip 210. [

The switching unit 220 electrically connects the tip 210 and the receiver 230 for a first time when the tip 210 is in contact with the touch screen TSP of the display device 20 , And electrically connects the tip 210 and the driving unit 240 during the second time period, thereby temporally separating the reception timing of the touch screen drive signal and the transmission timing of the modulation pen drive signal. Since the tip 210 serves also as a receiving electrode and a transmitting electrode, the structure of the active touch pen 20 is simplified.

The receiving unit 230 may include at least one amplifier to amplify the touch screen driving signal input from the tip 210 through the switching unit 220. The receiving unit 230 includes a comparator, compares the amplified signal with a preset reference voltage, and outputs the result to the signal processing unit 250.

The signal processing unit 250 generates a pen driving signal synchronized with the touch screen driving signal by analyzing the comparator output signal inputted from the receiving unit 230 for more than one frame and then outputs the pen driving signal to the pressure sensing unit (not shown) connected to the tip 210, And outputs the modulated pen driving signal to the driving unit 240. The modulating pen driving signal is supplied to the driving unit 240,

The driving unit 240 includes a level shifter 243 to shift the voltage level of the modulation pen driving signal. The driving unit 240 outputs the level-shifted modulation pen driving signal to the tip 210 through the switching unit 220.

The input / output interface 270 is connected to the power supply unit 260 according to a button push operation of the user, and can supply necessary power to the receiving unit 230, the driving unit 240, and the signal processing unit 250.

Referring to FIG. 12, the operation of the pressure sensing unit 215 will be described below.

The pressure sensing unit 215 includes a vertical pressure sensing unit 216 and a pressure sensing unit 217.

The vertical pressure sensing unit 216 senses a pressure F1 applied perpendicularly to the longitudinal direction of the tip 210 when the tip 210 contacts the touch screen TSP. When the vertical pressure F1 is applied to the tip 210, the tip 210 is bent and the vertical pressure sensing portion 216 moves the vertical pressure F1 'applied when the tip 210 is bent And obtains the vertical pressure information. The pressure sensing unit 217 senses the pressure F2 applied in the longitudinal direction of the tip 210 to acquire the pressure information.

The receiving unit 230 of the active touch pen 20 includes a receiving buffer 231, an amplifier 233, and a comparator 235. The reception buffer 231 receives the touch screen driving signal Ts transmitted through the switching unit 220 and applies the received touch screen driving signal Ts to the amplifier 233. The amplifier 233 includes at least two stages to amplify the touch screen driving signal Ts at the analog level to increase the sensitivity of the received signal. The comparator 235 compares the amplified signal from the amplifier 233 with an internal reference voltage to generate a comparator output signal COM at a digital level above the reference voltage or below the reference voltage. Here, when the amplifier 233 is implemented as an inverting amplifier, the comparator 235 uses a signal equal to or higher than the reference voltage as the comparator output signal COM. When the amplifier 233 is implemented as a non-inverting amplifier, Can be used as the comparator output signal COM.

The signal processing unit 250 of the active touch pen 20 determines the timing of synchronizing with the touch screen driving signal Ts based on the comparator output signal COM as described above and then outputs the pen driving signal . The signal processing unit 250 modulates the pen driving signal based on the pressure information input from the pressure sensing unit 215 and outputs the pen driving signal Ps reflecting the pressure information.

The pressure information included in the pen drive signal Ps includes vertical pressure information and pressure information. The vertical pressure information is used by the touch driver to calculate the touch compensation coordinates. A method of calculating the touch correction coordinates by using the vertical pressure information of the touch driving device will be described later.

The touch pen 20 adjusts the amplitude and / or the number of pulses of the modulation pen driving signal Ps according to the signal level of the pressure information, and the driving unit 240 of the active type touch pen 20 outputs the pressure information to the level shifter 243 and a transmission buffer 241 and converts the modulation pen drive signal Ps input from the signal processing unit 250 into an analog level and outputs the analog level to the switching unit 220. [ Then, the switching unit 220 transmits the modulation pen driving signal Ps to the tip 210. [

13 is a diagram showing a touch screen driving signal and a pen driving signal in a touch sensor driving period.

After the active touch pen 20 is brought into contact with the touch screen TSP following the on operation of the active touch pen 20, the reception section Ra of the touch screen drive signal Ts and the modulation pen drive signal Ps, The signal switching period of at least one frame is provided between the transmission period Ta of the transmission period Ta and the operation stability is ensured. The signal processing unit 250 determines the synchronization timing using the signal switching period, and generates the modulation pen driving signal Ps by reflecting the pressure information accordingly.

In the subsequent frame, a process (Ta) of transmitting a modulation pen driving signal (Ps) synchronized with the touch screen driving signal (Ts) to the touch screen (TSP) through the tip (210) The process (Ra) of receiving the screen driving signal (Ts) is repeatedly and alternately performed.

The driving signal Ps of the touch pen 20 includes the sensing signal output period period 1 and the additional information output period period 2. The sensing signal output period period 1 is a period during which a sensing signal for recognizing touch coordinates is output, and the additional information output period period 2 is a period during which additional information such as vertical pressure information and pressure information is output.

14 is a flowchart illustrating a method of compensating touch coordinates by a touch driving device based on vertical pressure information acquired by a touch pen. The touch correction algorithm described below can be performed by the touch correcting unit 180 shown in Figs.

Referring to Fig. 14, when the pen drive signal Ps is transmitted, the touch input calculating unit 1811 of the touch driver 180 calculates pen touch coordinates and palm peak coordinates. The pen touch coordinates are coordinates of a point at which the drive signal Ps of the touch pen 20 is transmitted, and the palm coordinates are one of coordinates of a touch of the user's hand on the touch screen TSP.

As shown in FIG. 15, it is general that the user's hand touches the touch screen TSP in the process of contacting the touch pen 20 with the touch screen TSP. Therefore, when using the touch pen 20, the touch input calculation unit 181 acquires a plurality of touch coordinates. The touch input calculating unit 181 of the touch driving device 18 divides a plurality of touch coordinates into pen touch coordinates P1 and palm coordinates P2-1 to P2-11 as shown in FIG. The pen touch coordinates P1 and the palm coordinates P2-1 to P2-11 may be used to label touch coordinates and determine the number based on the number of labeled touch coordinates. In the touch screen TSP, the number of touch sensors whose capacitances are changed by the touch pen 20 is one or several, whereas the number of touch sensors whose capacitances are changed by the user's hand is very large. Accordingly, the touch correcting unit 180 sets the small number of labeled touch coordinates to the pen touch coordinates P1, and the touch coordinates consisting of a relatively large number of labels to the palm coordinates P2-1, P2-11, .

The touch input calculation unit 181 sets the palm peak coordinates (x ', y') among the palm coordinates ((P2-1, P2-11)). The touch input calculating unit 181 calculates one of the regions where the touch pen 20 is located as the palm peak coordinate P2 when the touch pen 20 is projected in the vertical direction on the touch screen TSP (S103)

The horizontal angle calculating unit 183 calculates the palm peak coordinate (P2) direction from the pen touch coordinates (P1) to the tip horizontal vector (V_T). The horizontal angle calculation unit O calculates a trigonometric function for the horizontal angle (?) Formed by the reference axis and the tip horizontal vector (V_T). The reference axis L can use either x-axis or y-axis in the touch coordinate system. Fig. 17 shows an example in which the x-axis passing through the pen touch coordinates P2 is set as the reference axis L. Fig.

In order to calculate the trigonometric function with respect to the horizontal angle [theta], the horizontal angle calculating unit 183 sets the distance c from the pen touch coordinate P1 to the palm point coordinate P2 as a hypotenuse, The absolute value of the x coordinate component difference between the pen touch coordinates P1 and the palm peak coordinates P2 is set as the height a and the absolute value of the x coordinate component difference between the pen touch coordinates P1 and the palm peak coordinates P2 as the base b The right triangle is set.

The horizontal angle calculating section 183 calculates cos? And sin? With respect to the horizontal angle?. The horizontal angle calculator 183 calculates cos &thetas; by calculating b / c. The horizontal angle calculating unit 183 calculates sin a &thetas; by calculating the ratio a / c. At this time, the hypotenuse (c) can be calculated using the Pythagorean theorem (S105)

The error length calculating unit 185 calculates the error length based on the vertical pressure information included in the additional information output period period2 in the pen drive signal Ps. The error length (L) refers to the degree to which the actual touch input coordinates are distorted according to the degree to which the tip 210 is tilted in the vertical direction of the touch screen TSP, as shown in FIG. 9, the gap between the tip 210 and the touch screen TSP is narrowed in the direction in which the tip 210 is tilted. Therefore, the tip 210 is moved in the radial direction by the drive signal transmitted from the tip 210, A capacitance change occurs between the touch screens (TSP). As a result, the area where the tip 210 contacts the touch screen TSP is the point P3. However, the touch input calculation unit 181 calculates the point P1 at which the tip 210 is deflected in the tilted direction, . The degree to which the touch input coordinate P1 is deflected from the touch coordinate P3 is proportional to the tilt degree of the tip 210. [ The magnitude of the vertical pressure F1 applied in the vertical direction of the tip 210 also increases according to the degree of tilting of the tip 210. [ Conversely, the error length calculating unit 185 can calculate the error length (l) indicating the deviation from the contact coordinate P3 to the touch input coordinate P1 based on the vertical pressure information in the touch drive signal Ts have. The error length l may be matched one-to-one with the vertical pressure information and stored in a preset lookup table, and the error length calculator 185 may extract the error length matched with the vertical pressure information in the lookup table. S105)

The touch input correcting unit 187 compensates the touch coordinates in the direction of the note vector in the direction opposite to the tip horizontal vector V_T in the pen touch coordinates. The touch input correction unit 187 sets the error length to the magnitude of the compensation value. That is, the touch input correction unit 187 can calculate the touch coordinates P3 using the horizontal angle? And the error length? In the touch input coordinate P1.

The x-axis coordinate (x ") of the contact coordinate (P3) is calculated by the following equation (1).

[Equation 1]

x "= x + error length (l) * cos &thetas;

The y-axis coordinate (y ") of the contact coordinate (P3) is calculated by the following formula (2).

&Quot; (2) "

y "= x + error length (l) * sin &thetas;

As described above, the present invention can correct the inclination of the touch pen 20 and the deviation of the touch input coordinates. Accordingly, since the point at which the user touches the touch pen 20 can be obtained more accurately, the accuracy of the touch can be increased, and as a result, the usability of the touch screen can be improved through precise touch input.

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: touch pen 215: pressure sensing unit
216: Vertical pressure sensing unit 217: Pressure sensing unit
210: Tip 220:
230: Receiving unit 231: Receiving buffer
233: Amplifier 235: Comparator
240: driving unit 241: transmission buffer
243: level shifter 250: signal processor

Claims (13)

An active touch pen for outputting a pen driving signal for correcting the touch coordinates according to a tip angle by a touch driving device for calculating touch coordinates by sensing a capacitance change of a touch screen,
A tip for outputting the pen drive signal;
A vertical pressure sensing unit sensing a vertical pressure applied to the tip in a vertical direction according to a slope of the tip when the tip contacts the touch screen; And
And a signal processing unit for transmitting the vertical pressure detected by the vertical pressure sensing unit to the touch driving device. The method according to claim 1,
Wherein the vertical pressure sensing unit comprises a plurality of pressure sensors arranged to surround a periphery of an end region of the tip. 3. The method of claim 2,
The pen drive signal
A sensing signal output period for sensing a touch input of the touch screen; And
And an additional information output period including vertical pressure information obtained by the vertical pressure sensing unit. touch screen;
A touch driving device for applying a touch driving signal to the touch screen and sensing a capacitance change of the touch screen to calculate a plurality of touch input coordinates; And
A pen driving signal synchronized with the touch driving signal is transmitted through a tip and pressure information is generated by sensing a pressure applied in the vertical direction of the tip when the tip contacts the touch screen, And an active touch pen provided to the touch driving device,
The touch-
A touch input calculation unit for calculating pen touch coordinates and palm peak coordinates according to the number of labels in the plurality of touch input coordinates;
A horizontal angle calculation unit for calculating the palm peak coordinate direction as a tip horizontal vector in the pen touch coordinates and calculating horizontal angle information formed by the reference axis and the tip horizontal vector in the touch coordinate system;
An error length calculating unit for calculating an error length of the pen touch coordinates based on the pressure information; And
And a touch input correction unit that calculates a touch correction coordinate obtained by compensating the error length in a direction of a tone vector in a direction opposite to the tip horizontal vector in the pen touch coordinates. 5. The method of claim 4,
The touch input calculating unit
The touch input coordinates having a large number of labels among the plurality of touch input coordinates are set as palm coordinates,
And sets coordinates arbitrarily selected from among the palm coordinates to palm peak coordinates. 5. The method of claim 4,
The horizontal angle calculating unit
An absolute value a of the difference between the y-coordinate component of the pen touch coordinate and the palm peak coordinate,
An absolute value b of the x coordinate component difference between the pen touch coordinate and the palm peak coordinate,
Calculates a distance c between the pen touch coordinates and the palm peak coordinates,
And calculates a trigonometric function for the horizontal angle according to the proportions of a, b, and c. 5. The method of claim 4,
The error length calculating unit
And calculates the error length to be proportional to the pressure applied in the vertical direction of the tip. The method according to claim 6,
The touch input correction unit
The x coordinate of the pen touch coordinates is corrected by multiplying the touch compensation length by b / c,
Wherein the touch compensation coordinate is calculated by multiplying the touch compensation length by a / c to correct the y coordinate of the pen touch coordinates. A method of driving a touch sensing system for sensing a touch input by an active touch pen for generating vertical pressure information by sensing a vertical pressure applied to a vertical direction of a tip,
Calculating pen touch coordinates and palm peak coordinates according to the number of labels in a plurality of touch input coordinates;
Calculating the palm peak coordinate direction as a tip horizontal vector in the pen touch coordinates and calculating horizontal angle information formed by the reference axis and the tip horizontal vector in the touch coordinate system;
Calculating an error length of the pen touch coordinates based on the vertical pressure information; And
And correcting the touch input by compensating the error length in a direction of a tone vector in a direction opposite to the tip horizontal vector in the pen touch coordinates. 10. The method of claim 9,
The step of calculating the touch input
Setting palm coordinates of touch input coordinates having a large number of labels among a plurality of touch input coordinates; And
And setting coordinates arbitrarily selected from the palm coordinates to palm peak coordinates. 10. The method of claim 9,
The step of calculating the horizontal angle information
Calculating an absolute value a of a difference between the y-coordinate component of the pen touch coordinate and the palm peak coordinate;
Calculating an absolute value b of the x coordinate component difference between the pen touch coordinate and the palm peak coordinate;
Calculating a distance c between the pen touch coordinates and the palm peak coordinates; And
And calculating a trigonometric function for the horizontal angle according to the proportions of a, b, and c. 10. The method of claim 9,
Wherein the step of calculating the error length calculates the error length so as to be proportional to the pressure applied in the vertical direction of the tip. 13. The method of claim 12,
The step of calibrating the touch input
Correcting the x coordinate of the pen touch coordinates by multiplying the touch compensation length by b / c; And
And correcting the y coordinate of the pen touch coordinates by multiplying the touch compensation length by a / c.

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