KR102279817B1 - Input System and Method for Detecting Touch Using the Same - Google Patents

Abstract

The present invention relates to an input system used as an input means for position detection and a touch detection method using the same, and the touch detection method using the input system of the present invention is to turn on an input pen provided by protruding a conductive tip. A first step, a second step of bringing a conductive tip of the input pen into contact with or approaching a display panel including a touch screen, and the conductive tip is coupled to the touch screen through the conductive tip, and the touch is performed at the contact or access portion. a third step of receiving a driving signal of the screen; a fourth step of generating a pen driving signal synchronized with a driving signal of the touch screen received at the contact or approach portion inside the input pen; and a fifth step of transferring to the touch screen through the tip.

Description

Input System and Method for Detecting Touch Using the Same}

The present invention relates to an input system, and more particularly, to an input system with improved detection accuracy and a touch detection method using the same.

Recently, as we enter the information age in earnest, the field of display that visually expresses electrical information signals has developed rapidly, and in response to this, various flat display devices with excellent performance of thinness, light weight, and low power consumption have been developed. It has been developed and is rapidly replacing the existing cathode ray tube (CRT).

Specific examples of such flat panel display devices include a liquid crystal display (LCD), a plasma display panel device (PDP), a field emission display device (FED), an electroluminescence display ( Electro Luminescence Display Device (ELD), etc., which commonly use a flat panel display panel that implements an image as an essential component, and the flat panel display panel is a pair of flat panel display panels with a material layer having inherent light emission or optical anisotropy interposed therebetween. It has a structure in which a transparent insulating substrate of

Recently, there has been an increasing demand for adding a touch panel capable of recognizing a touch part through a human hand or a separate input means and transmitting separate information in response to the display device formed as described above. Currently, such a touch panel is applied in the form of being attached to the outer surface of the display device.

In addition, according to the touch sensing method, it is divided into a resistive method, a capacitive method, an infrared sensing method, and the like, and the capacitive method is recently attracting attention in consideration of the convenience and sensing power of the manufacturing method.

On the other hand, as a mobile device that is mainly considered recently, a smart phone, a smart book, etc. as a human interface device (HID), as well as a touch input using a finger, as well as a stylus pen capable of writing or drawing using a pen are increasingly used as input devices. trend to apply. The stylus pen input has advantages such as enabling more detailed input compared to input with a finger, and supporting functions such as detailed drawing and writing.

However, the stylus pen needs to add a separate sensor and electrode in addition to the electrode provided for the touch panel in order to recognize the input, and there is a problem in the process and cost burden due to this.

In addition, in the case of a method in which the touch panel is attached to the display panel, it may be easy to add electrodes and sensors. However, when the touch panel is integrally provided with an array inside the display panel, the addition of electrodes and sensors is fairly straightforward. There are difficulties, and there may be a phenomenon in which the driving of the touch panel affects the driving of the display panel, so it is not easy to add such electrodes and sensors.

The present invention has been devised to solve the above problems, and provides an input system and a touch detection method using the same, in which a touch screen is embedded in a display panel in an in-cell type, and the detection accuracy is improved without an additional electrode for the input pen. it's about

An input system of the present invention for achieving the above object includes a display panel having a touch screen including a plurality of electrodes for detecting touch, a conductive tip, a switching unit connected to the conductive tip, and parallel connection with the switching unit, , a receiving unit receiving the driving signal of the touch screen from the conductive tip, a driving unit transmitting a pen driving signal to the conductive tip, and correcting the timing of the pen driving signal to synchronize with the driving signal of the touch screen applied from the receiving unit and a housing that exposes a portion of the signal processing unit and the conductive tip, and has the switching unit, the receiving unit and the driving unit, and the signal processing unit therein.

When the conductive tip comes into contact with or approaches the display panel, it is coupled to a contact portion or an electrode for detecting the closest touch to receive a driving signal of the touch screen.

In addition, the conductive tip generates the pen driving signal, which is timing-corrected by the signal processing unit, after a predetermined period of time has elapsed after receiving the driving signal of the touch screen, and transmits it to the display panel.

The conductive tip may have a transition period of one frame or more between receiving a driving signal of the touch screen and transmitting the pen driving signal.

The housing may further include a pressure sensor physically connected to the conductive tip, sensing an amount of pressure applied to the conductive tip, and transmitting it to the signal processing unit.

The signal processing unit may control the switching unit by dividing the pen driving signal generation period and the pen sensing period.

The receiver may further include an amplifier for amplifying the signal sensed by the switching unit and a comparator for outputting a digital level pen sensing signal by comparing the amplified signal with a threshold value.

The signal processing unit may receive the digital level pen sensing signal from the comparator and output a pen driving signal timing synchronized with the driving signal of the touch screen.

The driving unit may include a level shifter that outputs the digital logic level pen driving signal applied from the signal processing unit as an analog driving voltage signal.

A power supply connected to the signal processing unit and supplying power may be further included in the housing.

It may further include an input/output interface connected to the power supply and protruding from the surface of the housing.

In addition, the touch detection method using the input system of the present invention for achieving the same object is a first step of turning on the input pen provided with the conductive tip protruding; and, the conductive tip of the input pen is applied to the touch screen A second step of contacting or approaching a display panel including a; and a third step of coupling with the touch screen through the conductive tip and receiving a driving signal of the touch screen at a contact or access portion; and a fourth step of generating a pen driving signal synchronized with a driving signal of the touch screen received from the contact or approaching portion inside the input pen; and a fifth step of transmitting the pen driving signal to the touch screen through the conductive tip.

And, after the fourth step, the conductive tip may time-division and repeat the third and fourth steps.

In addition, the display panel generates a touch enable signal divided into one or more alternating display sections and touch sections per frame, the touch screen generates driving signals for a plurality of touch screens in the touch section, and the input pen by time-dividing the touch section, an initial part of the touch section performs the third step, and the remaining section of the touch section performs the fourth step.

The third step may include receiving and amplifying a driving signal of the touch screen to output an amplified signal, and outputting a digital level pen sensing signal by comparing the amplified signal with a threshold value.

In the touch period, the pen sensing signal of the digital level is terminated, and after delaying one clock or more of the driving signal of the touch screen, a pen driving signal synchronized with the driving signal of the touch screen may be output.

The fourth step may be performed by processing a signal received through the conductive tip for a predetermined time to initialize the timing of the pen drive signal.

The method may further include a sixth step of detecting a position by sensing a change in capacitance of the touch detection electrode of the touch screen coupled to the conductive tip.

The input system and the touch detection method using the same of the present invention as described above have the following effects.

Even if a separate electrode for driving the input pen is not added on the display panel, the conductive tip of the input pen is used as a medium for receiving the driving signal of the touch screen in the display panel, and the pen driving signal generated in the input pen is used. By using it as a medium for transmitting , it is possible to simplify the structure even in a state where high sensitivity of touch sensing is maintained.

The input pen does not independently generate the pen drive signal, but receives the drive signal of the touch screen and generates the pen drive signal Ps based on this, and accurately detects whether the pen is in contact with the drive section (Tx) of the touch screen. Therefore, the accuracy of touch detection can be ensured. Accordingly, it is possible to implement a high-sensitivity input pen.

In addition, the linearity of touch detection can be maintained, so that touch performance can be improved.

Since the sensing capacitor is formed by coupling the conductive pen provided in the input pen and the touch screen, the signal in the input pen can be corrected, and it is not required to form an electromagnetic sensor of the display panel for driving the input pen, so that in the structure It is possible to implement a simplified touch screen, and is particularly useful for an in-cell type structure.

However, the input system of the present invention is not limited to the in-cell type touch screen structure, and any electrode structure of the touch screen may be applied as long as it has a capacitive type. In addition, the detection method is applicable to mutual capacitance detection (Mutual Capacitance Type) in addition to the self-capacitance type.

In addition, in the input system of the present invention, the conductive tip alternates the roles of pen sensing and transmission of the pen driving signal (S_Rx), and based on the signal received during sensing, the pen is synchronized with the frequency operating on the touch screen. By generating a driving signal and using it for touch detection, it is possible to synchronize a signal between a pulse operating on the touch screen and a pen driving signal driven by the stylus pen to improve the magnitude of the touch signal.

In addition, in an input system having an in-cell touch screen and an input pen driven in association with the in-cell touch screen, better touch sensitivity compared to a finger touch may be realized.

1 is a schematic diagram showing an input system of the present invention;
2 is a block diagram illustrating a display panel and a control unit thereof of an input system according to the present invention;
3 is a waveform diagram illustrating time division driving of a display panel of an input system according to the present invention;
4A and 4B are block diagrams illustrating in detail a touch screen of an input system and a touch control unit thereof of the present invention.
Figure 5 is a modification of Figure 4a
6 is a waveform diagram of a driving signal supplied to a touch detection electrode of the touch screen of FIG. 5
7 is a block diagram showing the internal structure of the input pen according to the first embodiment of the present invention;
8 is a flowchart illustrating the operation of the input pen of FIG. 7
9 is a waveform diagram illustrating a relationship between a driving signal of the touch screen of FIG. 7 and a pen driving signal;
10 is a waveform diagram for each configuration of the input pen of FIG.
11 is a view showing the operation of the conductive tip of the input pen of FIG. 7 over time;
12 is a block diagram showing the internal structure of the input pen according to the second embodiment of the present invention;
13 is a timing diagram of the internal configuration of the touch screen and the input pen of FIG. 12
FIG. 14 is a waveform diagram showing actual output from each component on the receiving unit side of the input pen of FIG. 12 ;
15 is a waveform diagram showing the sensitivity of a touch detection signal sensed when the input pen is touched compared to a finger when the input pen of the present invention is applied;

Hereinafter, an input system of the present invention and a touch detection method using the same will be described with reference to the accompanying drawings.

1 is a schematic diagram showing an input system of the present invention.

As shown in FIG. 1 , the input system of the present invention includes a display panel 200 having both a display function and a touch detection function, and an input pen 100 performing a touch detection function by contacting a specific area.

In addition, the display panel 200 is capable of detecting a touch by a finger other than the input pen 100 , and has a capacitive touch screen integrally formed therein. Here, the touch screen does not include a touch electrode of an independent configuration on a glass substrate, but a touch detection electrode and a connection wire thereof are formed in the same process as a pixel array provided for a screen display of the display panel 200 . As such, the supporting substrate can be omitted, so that the completed display panel 200 has substantially the same thickness and weight as that of the display panel having the original screen display function.

In some cases, it may be assumed that the touch screen is provided on the upper portion of the display panel 200 in an on-cell type. In this case, the touch screen may be attached to the rear side of the upper substrate of the display panel, and a polarizing plate or a protective film may cover the upper portion of the touch detection electrode constituting the touch screen.

Meanwhile, the display panel 200 may be a liquid crystal panel, a field emission display panel, a plasma display panel, an organic light-emitting diode display panel, an electrophoretic display panel, etc. In the following embodiments, as an example, a liquid crystal panel is used. explained in the center. However, the shape of the display panel 200 is not limited to the liquid crystal panel and may be changed and applied to various other flat panel display panels mentioned above.

For example, when the display panel 200 is implemented in the form of a liquid crystal panel, the electrodes constituting the touch screen may be simultaneously formed in the process of forming the wiring of the liquid crystal panel.

2 is a block diagram illustrating a display panel and a control unit thereof of an input system according to the present invention.

As shown in FIG. 2 , the display panel 200 of the input system of the present invention includes gate driving circuits 26 and 20 and a data driving circuit 24 as a pixel array driving circuit, and a touch sensing circuit 300 for driving a touch screen. ), all of which are connected to the timing controller 22, and they are housed in a single module (not shown).

When the display panel 200 is a liquid crystal panel, it includes a liquid crystal layer formed between two substrates. The substrates may be made of a glass substrate, a plastic substrate, a film substrate, or the like. The pixel array formed on the lower substrate of the display panel 200 includes data lines, gate lines crossing the data lines, and pixels arranged in a matrix form. The pixel array includes a plurality of TFTs formed at intersections of data lines and gate lines, pixel electrodes for charging the data voltage to the pixels, and a storage capacitor connected to the pixel electrodes to maintain the pixel voltage. and more.

The pixels of the display panel 200 are formed in a pixel area defined by the data lines D1 to Dm and the gate lines G1 to Gn and are arranged in a matrix form. Each liquid crystal cell of the pixels is driven by an electric field applied according to a voltage difference between the data voltage applied to the pixel electrode and the common voltage applied to the common electrode to control the amount of transmitted light. TFTs (Thin Film Transistors) are turned on in response to a gate pulse from the gate line to supply voltages from the data lines D1 to Dm to the pixel electrodes of the liquid crystal cell. The common electrode may be formed on the lower substrate or the upper substrate.

The upper substrate of the display panel 200 may include a black matrix, a color filter, and the like. A polarizing plate is attached to each of the upper and lower substrates of the display panel 200 , and an alignment layer for setting a pretilt angle of the liquid crystal is formed on the inner surface in contact with the liquid crystal. A 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 200 .

The display panel 200 may be implemented in any known liquid crystal mode, such as a twisted nematic (TN) mode, a vertical alignment (VA) mode, an in plane switching (IPS) mode, and a fringe field switching (FFS) mode.

Meanwhile, a backlight unit may be selectively disposed on the rear surface of the display panel 200 . The backlight unit is implemented as an edge type or direct type backlight unit to irradiate light to the display panel 200 .

The pixel array driving circuit writes input image data to pixels of the display panel 200 using the data driving circuit 24 and the gate driving circuits 26 and 30 .

The data driving circuit 24 converts digital video data RGB input from the timing controller 22 into analog positive/negative gamma compensation voltages to generate a data voltage. The data driving circuit 24 supplies a data voltage to the data lines under the control of the timing controller 22 and inverts the polarity of the data voltage.

The gate driving circuits 26 and 30 sequentially supply a gate pulse (or scan pulse) synchronized with the data voltage to the gate lines to select a line of the display panel 200 to which the data voltage is written. The gate driving circuit includes a level shifter 26 and a shift register 30 . Through a gate in panel (GIP) process, the shift register 30 may be directly formed on a substrate of the display panel 200 .

The level shifter 26 may be formed on a printed circuit board (hereinafter, referred to as “PCB”) 20 electrically connected to a lower substrate of the display panel 200 . The level shifter 26 outputs clock signals swinging between the gate high voltage VGH and the gate low voltage VGL under the control of the timing controller 22 . The gate high voltage VGH is set to a voltage greater than or equal to the threshold voltage of the TFTs formed in the pixel array of the display panel 200 . The gate low voltage VGL is set to a voltage lower than the threshold voltage of the TFTs formed in the pixel array of the display panel 200 . The level shifter 26 is a gate high voltage VGH and a gate low voltage VGL in response to the start pulse ST, the first clock GCLK, and the second clock MCLK inputted from the timing controller 22 , respectively. ) and output a start pulse VST and a clock signal CLK that swing between them. The clock signals CLK output from the level shifter 26 are sequentially shifted in phase and transmitted to the shift register 30 formed in the display panel 200 .

The shift register 30 is formed on the edge of the lower substrate of the display panel 200 on which the pixel array is formed so as to be connected to the gate lines of the pixel array. The shift register 30 includes a plurality of cascadingly connected stages.

The shift register 30 starts to operate in response to the start pulse VST input from the level shifter 26 , and shifts the output in response to the clock signals CLK to gate the gate lines of the display panel 200 . Pulses are supplied sequentially.

The timing controller 22 supplies digital video data RGB input from an external host system to integrated circuits (ICs) of the data driving circuit 24 . The timing controller 22 receives timing signals such as a vertical synchronization signal (Vsync), a horizontal synchronization signal (Hsync), a data enable signal (DE), and a clock input from an external host system, and receives the data driving circuit ( 24) and timing control signals for controlling the operation timing of the gate driving circuits 26 and 30 are generated. The timing controller 22 or the host system generates a synchronization signal SYNC for controlling operation timings of the pixel array driving circuit and the touch sensing circuit 300 .

The touch sensing circuit 300 senses a change in capacitance by applying a driving signal to wires of the touch screen and counting a voltage change of the driving signal before and after the touch or a delay time of a rising or falling edge of the driving signal. The touch sensing circuit 300 converts the sensing data received from the capacitance of the touch screen into digital data and outputs touch raw data. The touch sensing circuit 300 executes a preset touch recognition algorithm to analyze touch raw data to detect a touch (or proximity) input.

On the other hand, the wiring shape of the touch screen will be described in detail below.

3 is a waveform diagram illustrating time division driving of a display panel in an input system according to the present invention.

3 , the display panel 200 and the touch screen TSP may be time-division driven. That is, one frame period may be time-divided into a pixel array driving period T1 and a touch screen driving period T2.

“Vsync” is a first vertical synchronization signal input to the timing controller 22 , and “SYNC” is a second vertical synchronization signal input to the touch sensing circuit 300 . The timing controller 22 modulates the first vertical synchronization signal Vsync input from the host system to define the pixel array driving period T1 and the touch screen driving period T2 in one frame period to achieve the second vertical synchronization. The signal SYNC is generated or the host system generates the second vertical synchronization signal SYNC, and the timing controller 22 responds to the second vertical synchronization signal SYNC input from the host system during the pixel array driving period. (T1) and the touch screen driving period (T2) can be controlled. That is, the controller for time-dividing one frame period into a pixel array driving period and a touch screen driving period to control operation timings of the pixel array driving circuit and the touch sensing circuit may be any one of a timing controller and a host system.

For example, assuming that the display panel is driven at a frequency of 60 Hz, when the time division method is applied, 1/60 second becomes one frame period, and the period of one frame is again divided into the pixel array driving period T1 and the touch screen driving period. It is divided into period T2. As described above, the reason for dividing the pixel array driving and the touch screen driving by time division is that when the pixel array and the touch screen are driven at the same time, the driving interference between each other is severe, resulting in uneven display or poor touch detection accuracy. Therefore, to prevent this.

During the pixel array driving period T1 , the data driving circuit 24 supplies a data voltage to the data lines under the control of the timing controller 22 , and the gate driving circuits 26 and 30 generate gate pulses synchronized with the data voltage. is sequentially supplied to the gate lines. The touch sensing circuit 300 does not supply a driving signal to the wires of the touch screen during the pixel array driving period T1 .

Also, during the touch screen driving period T2 , the pixel array driving circuit is not driven and the touch sensing circuit 300 is driven. Accordingly, the touch sensing circuit 300 senses a touch (or proximity) input position by supplying a driving signal to wires of the touch screen during the touch screen driving period T2 .

Hereinafter, an example in which a touch screen used as an input system of the present invention has an in-cell type structure and is implemented as an example according to self-capacitance detection will be described.

4A and 4B are block diagrams illustrating in detail the touch screen of the input system and the touch control unit thereof of the present invention.

The touch screen according to the structure of FIG. 4A includes the touch detection electrodes COM1 , COM2 , ..., COMn for detecting the position of the input tool in the display panel 200 .

For example, if the display panel 200 is a liquid crystal panel having a pixel array on a lower substrate and a color filter array on an upper substrate, the touch detection electrode may be formed with the pixel array and the lower substrate, or It may be formed on the filter array, and in some cases, the common electrode formed on the lower substrate or the upper substrate may be patterned and used. If the touch detection electrodes COM1, COM2, ..., COMn are formed by patterning a common electrode, the touch detection electrode should function as a common electrode in driving the pixel array, so that a common voltage signal is uniformly applied do.

The touch detection electrodes COM1 to COMn are 1:1 connected to the sensing lines S1 to Sn, and the sensing lines S1 to Sn are connected to the touch sensing circuit 300 .

The touch sensing circuit 300 includes a receiving amplifier 30, an analog-to-digital conversion circuit 32, a detection unit 34, a storage unit 36, and a position calculation unit 38 inside, as shown in FIG. 4b. A receiver circuit group is provided.

In addition, the receiving circuit group is connected to a central processing unit (CPU) 40 connected to an external host. In addition, the central Youngsan processing unit 40 is connected to the control unit 42 for general control of the touch, and the control unit 42 is connected to the driving signal generation unit 46 to drive the touch generated by the oscillator 44 . The signal Ts is supplied to each of the touch detection electrodes COM1, COM2, ....COMN-1, COMN through the sensing lines S1 to Sn.

Here, the reason that the receiving system circuit group and the touch driving circuit 46 are provided in the touch sensing circuit 300 is that even when a non-powered driving input means such as a finger approaches or touches the touch screen itself, the touch to enable detection.

The touch screen in the drawing is a kind of self-capacitance method, and the electrodes COM1 to COMn for touch detection are used together to apply a driving signal and detect a received signal.

Each of the touch detection electrodes COM1 to COMn has a size larger than that of pixels, for example, is formed to overlap a plurality of pixels. In addition, since the transparent conductive material is formed, the aperture ratio is not reduced in the display period of driving the pixel array.

Meanwhile, a common voltage source (not shown) supplies the common voltage Vcom to the touch detection electrodes COM1 to COMn through the sensing lines S1 to Sn during the pixel array driving period T1 . Accordingly, the touch detection electrodes COM1 to COMn operate as common electrodes during the pixel array driving period T1. In addition, a selection circuit 50 for selecting the touch detection electrode is provided, and the selection circuit 50 is connected to the touch sensing circuit 300 .

The touch sensing circuit 300 is disabled during the pixel array driving period T1 and is enabled during the touch screen driving period T2 to transmit a touch driving signal only during the touch screen driving period T2 to the sensing lines S1 . ~Sn) at the same time.

FIG. 5 is a modified example of FIG. 4A , and FIG. 6 is a waveform diagram of a driving signal supplied to the touch detection electrode of the touch screen of FIG. 5 .

On the other hand, in the self-capacitance touch screen (TSP), as shown in FIG. 5 , a multiplexer 302 is provided at the signal input terminals of the touch detection electrodes COM1 to COMn in order to reduce the number of signal application wires from the touch sensing circuit 300 . In addition, a signal may be applied to the sensing lines S1 to Sn in a time division manner. The multiplexer 302 may be provided singly or in plurality. For example, when the multiplexer 302 is a 1:k (k is a natural number greater than or equal to 2 and less than n) multiplexer, the multiplexer 302 has n/k input/output pins (P1) between the touch sensing circuit 300 and the touch sensing circuit 300 . ~Pn/k), and in this case, as shown in FIG. 6 , the n touch detection electrodes COM1 to COMn are grouped into k, so that each of the k touch detection electrodes in each grouped group is the same. The driving signal Ts of the time-divided touch screen is applied. That is, the touch driving signal Ts of the same phase is applied to the first group of the touch detecting electrodes COM ₁ to COM _{k , and the second group of the touch detecting electrodes COM k +1} to COM _2k . In such a way that a touch driving signal shifted by a predetermined time width is applied to , the final n/k-th touch detection electrodes COM _(m-1)k+1 to COM _n ) (here, kxm = n) n/ The k shifted touch driving signals Ts are applied.

Meanwhile, the detection method of the touch screen of the above-described input system is a self-capacitance method, but is not limited thereto. It can also be applied to mutual capacitance detection (Mutual Capacitance Type) that detects whether a touch occurs by changing the capacitance between electrodes crossing each other as needed. Further, in the mutual capacitance detection type touch screen, the driving signal applying electrode and the detection signal electrode are disposed to cross each other, and may be provided together in an array inside the display panel, or may be separately provided outside the display panel. That is, the structure of the touch screen of the input system of the present invention is applicable to both in-cell type and on-cell type, and if it is a capacitive method, the specific method is mutually related to the self-capacitance detection method. Any of the dose detection methods can be applied.

Hereinafter, the structure and operation of the input pen synchronized with the touch screen will be described in detail.

*First embodiment*

7 is a block diagram showing the internal structure of the input pen according to the first embodiment of the present invention.

As shown in FIG. 7, the input pen used as the input tool of the present invention includes a housing 180, a conductive tip 110 protruding to the outside of one side of the housing 180, and the conductive tip ( 110) connected to the switching unit 120, the receiving unit 130 and the driving unit 140 connected in parallel with the switching unit 120, and receiving a signal received from the receiving unit 130, processing the signal to perform synchronization The signal processing unit 150 is connected to the signal processing unit 150 and includes the configuration of a power supply source 160 for supplying power and an external input/output interface 170 .

Meanwhile, the conductive tip 110 is made of a conductive material such as metal, and time-divided to serve as a receiving electrode and a transmitting electrode. The conductive tip 110 is coupled to the touch detection electrode COMx provided on the touch screen overlapping or closest to the display panel 200 when it comes into contact with or approaches the display panel 200 and receives a signal received from the corresponding touch detection electrode. or transmits the driving signal from the inside of the input pen to the touch screen.

For example, the display panel 200 has a polarizing plate or a protective film positioned on the uppermost side, and the polarizing plate or protective film is interposed between the touch detection electrode constituting the inner touch screen and the conductive tip 110 . Therefore, it functions as an insulating layer and a sensing capacitor Csen is generated between the conductive tip 110 and the touch detection electrode, and the conductive tip 110 contacts or contacts the display panel 200 . A touch position detection may be performed by reading a change in a value of a constant sensing capacitor Csen on the touch detection electrode of the corresponding portion from the touch sensing circuit. Here, when the display panel 200 of the conductive tip 110 is touched, more preferably, it is easy to detect a driving signal applied to the touch detection electrode, but the present invention is not limited thereto, and a predetermined distance on the display panel 200 is not limited thereto. It is possible to detect a driving signal even when the conductive tip 110 approaches within. This means that synchronization between pen driving of the input pen and driving of the touch panel is attempted even when the input pen does not touch the upper portion of the display panel 200 and is hovering, and touch recognition is achieved through synchronization. means

In addition, the switching unit 120 is directly electrically connected to the conductive tip 110 when the input pen 100 contacts the display panel 200 to determine whether the conductive tip 110 functions as a receiving electrode. Determines whether to function as a transmit electrode.

Since the amplitude of the signal received from the conductive tip is weak, the receiver 130 further includes an amplifier to amplify the received signal. Here, the signal received from the conductive tip 110 corresponds to the driving signal Ts of the touch screen applied to the touch detection electrode corresponding to the contact portion.

In an initial state, after the input pen is turned on, when the input pen contacts or approaches the display panel 200 , the conductive tip 110 moves through the switching unit 120 to the receiving unit 130 . is directly connected to , and the receiving unit 130 amplifies the received driving signal Ts of the touch screen through an amplifier provided therein so that the signal processing unit 150 uses it.

In addition, the signal processing unit 150 analyzes one or more frames of the amplified signal received through the receiving unit 130 , generates a signal with a timing synchronized with the driving signal Ts of the touch screen, and transmits it to the driving unit 140 . .

In addition, the driving unit 140 includes a level shifter and synchronizes with the timing of the driving signal Ts of the touch screen, and generates a driving signal Ps of the input pen swinging between a set high voltage and a low voltage, , and transmits it to the conductive tip 110 through the switching unit 120 .

Meanwhile, a power supply 160 and an input/output interface 170 are provided in the housing 180 to control the on-drive of the input pen 100 through the input/output interface 170 from the outside, and the The input/output interface 170 is connected to the power supply source 160 inside the housing 180 , and supplies necessary power to the receiving unit 130 , the driving unit 140 , and the signal processing unit 150 .

Here, the input/output interface 170 may be electrically connected to the power supply 160 by a pressing operation, and the operation of the input pen may be controlled by a user pressing operation.

8 is a flowchart illustrating an operation of the input pen of FIG. 7 .

First, power is supplied into the input pen 100 through the input/output interface 170 and the power supply source 160 (10S).

The conductive tip 110 contacts a predetermined portion of the display panel 200 ( 20S).

The conductive tip 110 is directly coupled to an electrode for detecting a touch in the display panel at an initial contact point of the display panel, and senses a driving signal of the touch screen received from the electrode for detecting the touch of the touch screen. to (30S).

The receiving unit 120 includes an amplifier, amplifies the received signal, and transmits it to the signal processing unit 150, and the signal processing unit 150 finds a timing synchronized with the signal from the touch detection electrode (40S). ). In addition, the signal processing unit 150 is provided with a comparator internally to compare the input amplified signal with a predetermined threshold value, compare the threshold value, and select when the input amplified signal is equal to or less than the threshold value, and the digital level pen sensing signal can also be printed.

Meanwhile, the signal processing unit 150 analyzes the signal applied from the receiving unit 120 to find the synchronized timing between the received signal and the pen drive signal Ps generated from the input pen. For example, it is performed in an interval of one frame or more.

The reason for providing a period of one frame or more in the signal correction is to sufficiently correct a phase difference between the received driving signal Ts on the touch screen side and the pen driving signal Ps.

One actual frame is not used for touch, and is divided into a pixel array driving period (T1) and a touch screen driving period (T2), and a driving signal is received from the touch screen only in the touch screen driving period (T2), and the signal processing unit ( 150), after sufficiently receiving the touch driving signal of the touch screen within a period of one frame or more, a synchronization timing thereof is determined.

Here, when the phase error between the driving signal Ts of the touch screen and the pen driving signal Ps is greater than a default value, a separate calibration algorithm may be further performed.

Next, a driving signal is generated by swinging with a signal between a predetermined high voltage and a low voltage set by the driving unit 140 in accordance with the timing information output from the signal processing unit 150 (50S).

Next, the driving signal converts the conductive tip 110 into a driving electrode through the switching unit 120 and supplies the pen driving signal Ps to the touch screen through the conductive tip (60S).

Here, following the ON operation of the input pen for the first time, after the input pen touches the touch screen, the receiving section Rx of the driving signal Ts of the touch screen and the transmitting section Tx in which the pen driving signal Ps is transmitted to the touch screen side ), a transition period of a predetermined period is provided, which is used for signal correction of the signal processing unit 150 .

In subsequent frames, the process of transmitting the pen driving signal (Ps) synchronized with the driving signal (Ts) of the touch screen through the conductive tip (Tx) and the process of receiving the driving signal of the touch screen using the conductive tip (Rx) ) is repeatedly time-divided. After the initial pen driving signal Ps is synchronized with the driving signal Ts of the touch screen, the switching section between the receiving section Rx and the transmitting section Tx of pen driving is omitted in the following frames, and the touch sensing section The driving may be performed by time-divisioning the receiving section and the transmitting section in the .

On the other hand, after the pen driving signal is driven to the touch screen, a change in capacitance between the conductive tip 110 and the coupled electrode COMn of the touch screen is sensed, and the touch screen is touch sensing. It is connected to the circuit 300 and detects a touch position through a touch sensing algorithm.

9 is a waveform diagram illustrating a relationship between a driving signal and a pen driving signal of the touch screen of FIG. 7 , and FIG. 10 is a waveform diagram of the input pen of FIG. 7 for each configuration.

As shown in FIG. 10, the conductive tip of the input pen functions as a receiving electrode by turning on the first power supply, receiving (Rx) a signal from the touch detection electrode, and passing through a switching period of a certain time, the The pen drive signal is received from the transmitter, and the pen drive signal is transmitted by itself switching to the transmitting electrode (Tx).

Here, in the switching period, the receiving unit in the input pen detects the waveform of the signal (the driving signal of the touch screen) received with the conductive tip as it is, and forms a received signal having a predetermined amplitude through an amplifier for predetermined processing.

Then, the signal processing unit generates a timing synchronized with the received signal based on the received signal (the driving signal of the touch screen) received through the receiving unit.

Then, the transmitter swings between the set low voltage and the high voltage, and generates a pen driving signal at the timing of the signal analyzed by the signal processing unit.

Meanwhile, as shown in FIG. 9 , after synchronizing the pen driving signal Ps with the driving signal Ts of the touch screen, the driving signal Ts of the touch screen is generated within the touch sensing period T2 in each subsequent frame. The pen driving signal Ps may be generated only in a section corresponding to .

In addition, as shown in FIG. 10 , although the time widths of the transmission section Tx and the reception section Rx are shown to be equal, the time of the reception section Rx is substantially related to the touch response speed, so it should be small. The better, the larger the time width of the transmission section Tx.

FIG. 11 is a view showing the operation of the conductive tip of the input pen of FIG. 7 over time.

11 , the conductive tip waits without generating a pen driving signal in the input pen when the input pen is switched on and is in contact with the display panel having the touch screen, and the conductive tip only receives during the waiting time. do Here, the received signal corresponds to the driving signal Ts of the touch screen.

And, after the signal reception is finished, the generation of the pen driving signal is initialized for a certain period of time, which means the transition period in which the aforementioned conductive tip is switched from the receiving electrode to the transmitting electrode, which may be one frame or more, During this period, the signal processing unit in the pen analyzes the received signal to generate a pen drive signal Ps synchronized with the received signal.

Accordingly, when the touch screen side detects whether or not a touch has been made, a change in capacitance occurs in the touch detection electrode corresponding to the part touched or approached by the input pen corresponds to the application of the driving signal Ts of the touch screen, and at the sensing time point, the input pen Capacitance changes due to contact (or approach) occur synchronously, enabling accurate touch location detection.

* Second embodiment *

The following second embodiment embodies the configuration of the driving signal generating/receiving unit 1000 of the input pen of FIG. 7 , and shows the driving signal generation and sensing of the input pen in more detail.

12 is a block diagram showing the internal structure of the input pen according to the second embodiment of the present invention.

12 shows the configuration of the driving signal generating/receiving unit 1000 of the input pen of FIG. 7 . The driving signal generating/receiving unit 1000 of the input pen may be included in the housing 180, and the second embodiment In addition, as shown in FIG. 7 , it is apparent that the housing 180 may further include a power supply source 160 for supplying power connected to the signal processing unit 345 and an external input/output interface 170 .

As shown in FIG. 12 , the driving signal generating/receiving unit 1000 of the input pen according to the second embodiment is largely in direct contact with the touch screen (see 200 of FIG. 1 ) or by hovering over the touch screen, so that the input pen The input/output terminal 305 receives a signal from the conductive tip of the and transmits the internally generated pen driving signal, the receiving unit 330 that processes the pen sensing signal S_Rx inside the input pen, and the pen driving signal S_Tx and a driving unit 340 that performs generation-related processing.

Here, the pen sensing signal S_Rx uses a driving signal generated from the touch screen by being coupled to the touch electrode or the closest touch electrode from the touch screen, and is amplified based on the analog level signal received from the receiving unit 330 . It is used for pen sensing through the process and its conversion to a digital signal. That is, a signal received by being coupled to the touch screen is used for pen sensing without separately generating a pen sensing signal inside the input pen.

In addition, the input/output terminal 305 includes a physical conductive tip 310 , a switching unit 320 and a pressure sensor 315 connected to the conductive tip 310 , respectively. The pressure sensor 315 may be optionally provided, but when provided, has the advantage of generating a pen driving signal according to the detected pressure level, so that the sensitivity of the input pen can be improved when a touch event occurs.

In addition, the switching unit 320 and the pressure sensor 315 have electrical and physical connections with the conductive tip 310 , respectively.

The receiving unit 330 includes a receiving buffer 331 , an amplifier 333 , and a comparator 335 , and the comparator 335 is connected to the signal processing unit 345 . Although the signal processing unit 345 is included in the driving unit 340 in the drawing, the signal processing unit 345 processes a signal in relation to synchronization of a touch driving signal of the touch screen 200 and generation of an internal pen driving signal. Controls both the 330 and the driving unit 340 , and also controls transmission of an on signal to the switching unit 320 .

The receiving buffer 331 receives the signal received from the touch screen 200 through the conductive tip 310 according to the selection of the receiving unit 330 in the switching unit 320 and transmits it to the amplifying unit 333 . . In some cases, the receiving buffer 331 may be omitted, and the switching unit 320 may be directly connected to the amplifying unit 333 .

The amplifier 333 may include a plurality of stages to increase the amplitude of the received sensing signal to improve sensitivity.

In addition, the comparator 335 compares the sensing signal output through the amplifier 333 with a threshold value, and outputs a digital level pen sensing signal with respect to a threshold value above or below the threshold value.

In addition, the driving unit 340 receives the digital level pen sensing signal output from the comparator 335 , and generates a pen driving signal, the signal processing unit 340 , and the digital level pen driving unit output from the signal processing unit 340 . It includes a level shifter 343 for converting a signal into an analog-level pen driving signal, and a transmission buffer 341 for transferring a signal from the level shifter 343 to the switching unit 320 . Here, the transmission buffer 341 may be omitted, and in this case, the level shifter 343 may be directly connected to the switching unit 320 .

The switching unit 320 is connected to the receiving buffer 331 of the receiving unit 330 and the transmitting buffer 341 of the transmitting unit 340, respectively, and according to the selection of the switching unit 320, the receiving buffer from the conductive tip 310 ( The sensed signal is transmitted to the 331 , or the pen driving signal transmitted from the transmission buffer 341 is transmitted to the conductive tip 310 . In addition, the switching unit 320 operates under the control of the signal processing unit 340 in relation to signal reception and transmission.

Here, the signal output from the comparator 335 is a pen sensing signal obtained by converting a signal above or below a threshold value among analog signals amplified by the amplifier into a digital level signal. In this case, whether a signal above the threshold value or a signal below the threshold value is used is related to whether the amplifier is inverted. For example, when the amplifier is an inverting amplifier, a signal below the threshold value is used, otherwise In this case, a signal above the threshold is used.

The pen sensing signal S_Rx and the pen driving signal S_Tx input and output to the signal processing unit 345 have digital levels, and the output pen driving signal S_Tx is converted from a digital level signal to an analog level signal in the level shift 343 . convert

Meanwhile, like the first embodiment, the conductive tip 310 of the input pen of the second embodiment is also made of a conductive material such as metal, and is time-divided to serve as a receiving electrode and a transmitting electrode. The conductive tip 310 is coupled to a touch detection electrode COMx provided on an overlapping or closest touch screen upon contact or approach on the display panel 200 , and a signal received from the touch detection electrode It receives or transmits a driving signal from the inside of the input pen to the touch screen.

For example, the display panel (see 200 of FIG. 1 ) has a polarizing plate or a protective film positioned on the uppermost side, and a polarizing plate or protective film is disposed between the touch detection electrode and the conductive tip 310 constituting the inner touch screen. is interposed, it functions as an insulating layer, and a sensing capacitor Csen is generated between the conductive tip 310 and the touch detection electrode, and the conductive tip 310 is connected to the display panel 200 . A touch position may be detected by reading a change in a value of a constant sensing capacitor Csen from the touch sensing circuit on the touch detection electrode of the corresponding portion when touching or. Here, when the display panel 200 of the conductive tip 310 is touched, more preferably, it is easy to detect the driving signal applied to the touch detection electrode, but the present invention is not limited thereto, and a predetermined distance on the display panel 200 is not limited thereto. It is possible to detect a driving signal even when the conductive tip 310 approaches within. This means that synchronization between pen driving of the input pen and driving of the touch panel is attempted even when the input pen does not touch the upper portion of the display panel 200 and is hovering, and touch recognition is achieved through synchronization. means

Hereinafter, the touch detection method according to the second embodiment of the present invention will be described in detail through a timing diagram.

13 is a timing diagram of the internal configuration of the touch screen and the input pen of FIG. 12 .

13 , the display panel 200 including the touch screen generates a touch enable signal that divides each frame into one or more alternating display periods D and touch periods T per frame. A low level of the touch enable signal is a touch period T, and a high level of the touch enable signal is a display period D. Here, in one frame, the display period D and the touch period T may be divided into dozens or more, as shown, and in some cases, as shown in FIG. 3 above, one display in one frame. It may be divided into a section (D) and a touch section (T).

In addition, the touch screen generates driving signals Ts of the plurality of touch screens in the touch period T.

In addition, the input pen time-divisions the touch section again, the receiving unit performs pen sensing for an initial part of the touch section, and the transmitting unit outputs the pen driving signal S_Tx.

Here, the driving signal Ts of the touch screen is sensed by the input pen and used for pen sensing, and outputs of the amplifier and comparator of the receiver are generated within the high-level section of the driving signal Ts of the touch screen.

In addition, the distinction between pen sensing and pen driving signals in the input pen is made through the control of the switching unit 320 , and the control signal of the switching unit 320 is generated by the signal processing unit 345 , and The control signal (Switch Ctrl) is changed from a low level to a high level, and the pen sensing is switched to the pen driving, and there is a delay of one clock or more of the driving signal Ts of the touch screen in this transition period. In addition, the pen driving signal is generated in synchronization with the falling edge or the rising edge of the driving signal of the touch screen generated after the delay, in synchronization with the clock of the driving signal of the touch screen. Here, it indicates that the driving signal of the touch screen and the pen driving signal S_Tx have inverted shapes (that is, the pen driving signal is generated in synchronization with the falling edge of the driving signal of the touch screen), and The pen driving signal of the driving signal Ts has the same clock. On the premise that the same clock is maintained, the driving signal Ts and the pen driving signal S_Tx of the touch screen may be inverted or have the same phase.

The delay in the transition period is preferably within 1 to 2 clocks of the driving signal Ts of the touch screen.

For each touch section T provided for each frame, the pen sensing and pen driving signal generation are repeated, and the pen sensing signal is required to set a timing synchronization signal for generating the pen driving signal. For coupling between the provided display panels, it may be desirable to secure the pen driving signal generation period relatively longer than the pen sensing period.

Hereinafter, a waveform diagram showing signals for each component observed in actual pen sensing by implementing the input system according to the second embodiment will be described.

In the example shown, the amplifier used a two-stage inverting amplifier.

FIG. 14 is a waveform diagram showing actual output of each component on the receiving unit side of the input pen of FIG. 12 .

As shown in FIG. 14, the driving signal of the touch screen generated from the touch screen shows a waveform of a certain period, but the signal that actually enters the receiving buffer through the conductive tip is a coupled signal, and the value that is not initially synchronized is small, As the load of the amplifier is applied in reverse, time passes, and the signal detected in the receive buffer is deformed.

Then, the receive buffer goes through a two-stage inverting amplifier, and the value is increased with the inverted signal.

Next, the comparator compares the final output of the inverting amplifier with the threshold again, inverts the value below the threshold, and outputs the digital level pen sensing signal.

Through this, it can be seen that the input system of the present invention does not generate a pen sensing signal inside the input pen, but generates a pen sensing signal using a driving signal of the touch screen and uses it for pen sensing.

On the other hand, the illustrated waveform diagram is simulated in a state where the input pen is not completely in contact with the touch screen, and when an actual touch is made, the output of the receiving buffer, the two-stage amplifier and the comparator changes at the touch point, and the When the pen driving signal synchronized with the driving signal of the screen is generated, it is determined by the controller connected to the touch screen to generate an event according to the touch.

15 is a waveform diagram illustrating the sensitivity of a touch detection signal sensed when the input pen is touched compared to a finger when the input pen of the present invention is applied.

As shown in Fig. 15, the intensity of the sensed signal is measured when the touch screen is touched with the input pen and when the input pen is touched with the finger by frame using the input system of the present invention. It can be seen that the strength of the sensed signal is large when the touch screen is touched, and the greater the value of the capacitance coupled between the touch screen and the conductive tip, the greater the strength. It was confirmed that a suitable level of signal detection was possible.

In the input system of the present invention, the conductive tip alternates the roles of pen sensing and transmission of the pen driving signal (S_Rx), and based on the signal received during sensing, the pen driving signal is synchronized with the frequency operating on the touch screen. is generated and used for touch detection, and the magnitude of the touch signal can be improved by synchronizing the signal between the pulse operating on the touch screen and the pen driving signal driven by the stylus pen.

In addition, in an input system having an in-cell touch screen and an input pen driven in association with the in-cell touch screen, better touch sensitivity compared to a finger touch may be realized.

On the other hand, the present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications and changes are possible within the scope without departing from the technical spirit of the present invention. It will be clear to those of ordinary skill in the art.

100: input pen 110: conductive tip
120: switching unit 130: receiving unit
140: driving unit 150: signal processing unit
160: power source 170: input/output interface
180: housing 200: display panel
300: touch sensing circuit 305: input/output terminal
310 conductive tip 315 pressure sensor
320: switching unit 330: receiving unit
331: receive buffer 333: amplifier
335: comparator 340: driving unit
341: transmit buffer 343: level shifter
345: signal processing unit

Claims (18)

a display panel having a touch screen including a plurality of electrodes for detecting touch; and
a conductive tip, a switching unit connected to the conductive tip, a receiving unit connected in parallel with the switching unit, receiving a driving signal of the touch screen from the conductive tip, and a driving unit transmitting a pen driving signal to the conductive tip; A housing having a signal processing unit correcting the timing of the pen driving signal and a portion of the conductive tip to be synchronized with the driving signal of the touch screen applied from the receiving unit, and having the switching unit, receiving unit and driving unit, and signal processing unit inside It consists of including an input pen made of including,
The conductive tip is coupled to a contact portion or an electrode for detecting a touch closest to the touch screen upon contact or approach to the display panel to receive a driving signal of the touch screen.
delete The method of claim 1,
The conductive tip generates the pen driving signal, which is timing-corrected by the signal processing unit, after a predetermined time elapses after receiving the driving signal of the touch screen, and transmits it to the display panel. 4. The method of claim 3,
The conductive tip has an input system, characterized in that it has a transition period of one frame or more between receiving the driving signal of the touch screen and transmitting the pen driving signal. The method of claim 1,
and a pressure sensor physically connected to the conductive tip, sensing an amount of pressure applied to the conductive tip, and transmitting it to the signal processing unit, in the housing. The method of claim 1,
The signal processing unit divides the pen driving signal generation period and the pen sensing period into an input system for controlling the switching unit. The method of claim 1,
The input system further comprising: an amplifier for amplifying the signal sensed by the switching unit; and a comparator for outputting a digital level pen sensing signal by comparing the signal amplified by the amplifier with a threshold value. 8. The method of claim 7,
The signal processing unit receives the digital level pen sensing signal from the comparator and outputs a pen driving signal in timing synchronization with the driving signal of the touch screen. 9. The method of claim 8,
The driving unit includes a level shifter configured to output the digital logic level pen driving signal applied from the signal processing unit as an analog driving voltage signal. The method of claim 1,
An input system connected to the signal processing unit and further comprising a power supply supplying power in the housing. 11. The method of claim 10,
The input system further comprising an input/output interface connected to the power supply and protruding from the surface of the housing. a first step of turning on an input pen provided by protruding a conductive tip;
a second step of contacting or approaching the conductive tip of the input pen on a display panel including a touch screen;
a third step of being coupled to the touch screen through the conductive tip and receiving a driving signal of the touch screen at a contact or access portion;
a fourth step of generating a pen driving signal synchronized with a driving signal of the touch screen received from the contact or approaching portion inside the input pen; and
and a fifth step of transmitting the pen driving signal to the touch screen through the conductive tip. 13. The method of claim 12,
After the fourth step, the conductive tip is time-divided and the third and fourth steps are repeated. 14. The method of claim 13,
The display panel generates a touch enable signal divided into one or more alternating display sections and touch sections per frame,
The touch screen generates driving signals for a plurality of touch screens in a touch section,
The input pen time-divisions the touch section, so that an initial part of the touch section performs the third step, and the remaining section of the touch section performs the fourth step. 15. The method of claim 14,
The third step may include receiving and amplifying a driving signal of the touch screen, outputting an amplified signal, and outputting a digital level pen sensing signal by comparing the amplified signal with a threshold value. detection method. 16. The method of claim 15,
Touch detection using an input system that outputs a pen driving signal synchronized with the driving signal of the touch screen after the digital level pen sensing signal ends in the touch section, delaying one clock or more of the driving signal of the touch screen method. 13. The method of claim 12,
In the fourth step, a signal received through the conductive tip is signal-processed for a predetermined period of time to initialize the timing of the pen drive signal. 13. The method of claim 12,
The touch detection method using an input system further comprising a sixth step of detecting a position by sensing a change in capacitance of the touch detection electrode of the touch screen coupled to the conductive tip.

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