KR102441159B1 - Noise robust active pen sensing device - Google Patents

Abstract

An active pen sensing device of the present invention comprises: a panel comprising a plurality of unit sensor electrodes; a sensor electrode control part that connects the plurality of unit sensor electrodes in a row or a column to form a sensing channel and form a reference signal group; a differential amplification circuit part comprising a differential amplifier that removes a common mode component from a signal detected by the sensing channel and a signal formed by the reference signal group; and a sensing circuit part comprising a detection part that detects an active pen signal from an output signal of the differential amplifier. Therefore, the present invention is capable of providing an advantage of improving an active pen sensing sensitivity.

Description

Noise-resistant active pen sensing device {NOISE ROBUST ACTIVE PEN SENSING DEVICE}

The present technology relates to an active pen sensing device that is robust against noise.

A technology for recognizing an external object that approaches or touches a touch panel is called a touch sensing technology. The touch panel is placed in the same position as the display panel on a flat surface. Accordingly, users can input a user manipulation signal to the touch panel while viewing the image of the display panel. This user manipulation signal generating method provides surprising user intuition compared to the previous other user manipulation signal input methods - for example, a mouse input method or a keyboard input method.

According to these advantages, touch sensing technology is applied to various electronic devices including display panels. The touch sensing device may sense a touch or proximity of an external object with respect to the touch panel by supplying a driving signal to a driving electrode disposed on the touch panel and receiving a reaction signal formed on the sensing electrode. The touch panel creates a capacitance between the driving electrode and the sensing electrode, and a change in the capacitance may indicate a touch or proximity of the external object.

Meanwhile, a user may use an active pen as well as a finger to input a user manipulation signal. Data communication between the active pen and the touch sensing device may go through the following process. When the touch sensing device transmits an uplink signal that can be recognized by the active pen, the active pen may receive the uplink signal and recognize the touch sensing device. Thereafter, when the active pen transmits a downlink signal that can be recognized by the touch sensing device, the touch sensing device may receive the downlink signal and recognize the active pen.

In an environment in which the active pen and its detection device are used, noise may be mixed in a signal output from the active pen, or the active pen detection device may not accurately distinguish the signal of the active pen according to various environmental changes. In this case, since the active pen signal and noise are received together, it is difficult to completely recognize the signal of the active pen.

When the distance between the active pen and the sensor electrode is close, the electrode detects a signal output from the active pen and the pen signal is recognized. However, in a device such as a panel used with an active pen, it is driven together with a display. A driving signal of the display may be transmitted through a parasitic capacitance formed between the display and the sensor electrode, and interference of the display driving signal forms noise unrelated to the signal of the pen in the sensing channel. Such noise may cause a malfunction in pen signal recognition or coordinate detection even in the absence of a pen.

SUMMARY OF THE INVENTION The present invention is intended to solve the problems of the prior art. An object of the present invention is to provide an active pen sensing device capable of effectively excluding the effect of noise provided through a display.

The active pen sensing device of the present invention forms a sensing channel by connecting a panel including a plurality of unit sensor electrodes and the plurality of unit sensor electrodes in a row or a column, and forming a reference signal group. a differential amplifier circuit including a sensor electrode control unit forming a sensor electrode control unit, a differential amplifier removing a common mode component from a signal detected from the sensing channel and a signal formed from the reference signal group; and a sensing circuit unit including a detection unit detecting a pen signal.

According to an embodiment of the present invention, the in-phase component is display noise.

According to an embodiment of the present invention, the sensor electrode control unit is connected to the plurality of unit sensor electrodes disposed in the same column of the panel.

According to an embodiment of the present invention, the active pen sensing device includes a plurality of the sensor electrode controllers, and the plurality of unit sensor electrodes are connected in the row by the plurality of the sensor electrode controllers.

According to an embodiment of the present invention, the sensing channel is two or more unit sensor electrodes connected in a row, and the reference signal group is two or more unit sensor electrodes connected in a row adjacent to or spaced apart from the sensing channel.

According to an embodiment of the present invention, the sensing channel is two or more unit sensor electrodes connected in a column, and the reference signal group is two or more unit sensor electrodes adjacent to or spaced apart from the sensing channel and connected in a column.

According to an embodiment of the present invention, the detection unit further includes a comparator for outputting a pulse obtained by comparing the magnitude of the output signal of the differential amplifier circuit with a reference level, and a sampling circuit for sampling the output signal of the differential amplifier circuit. do.

According to an embodiment of the present invention, the active pen sensing device includes a resistance correction circuit unit configured to match the resistance of the sensing channel viewed from the differential amplifier and the resistance of the reference signal group viewed from the differential amplifier. include more

According to an embodiment of the present invention, the resistance correction circuit unit includes a first compensator connected between one input of the differential amplifier and the sensing channel, and a second input unit connected between the other input of the differential amplifier and the reference signal group. It further includes a compensating unit and a compensation resistance calculating unit controlling resistances of the first compensating unit and the second compensating unit, respectively.

According to an embodiment of the present invention, the first compensator includes a plurality of resistors and the plurality of switches that are conductive to connect the plurality of resistors to a sensing channel, and the second compensator includes a plurality of resistors and the plurality of switches that are conductive to connect the plurality of resistors to a reference signal group.

According to an embodiment of the present invention, the compensation resistance calculating unit divides the difference between the average resistance value of the sensing channel and the average resistance value of the reference signal group by the number of the unit electrodes included in the sensing channel. Calculate the compensating resistance.

According to the noise-resistant active pen sensing device of the present invention, an effect of noise introduced from the display can be excluded, and thus the active pen sensing sensitivity can be improved.

1 is a diagram illustrating an outline of an active pen (PEN) according to the present embodiment.
2(a) to 2(b) are diagrams illustrating the operation mode of the active pen PEN and signals provided by the tip electrode TIP, the ring electrode RING, and the tail electrode TAIL for each operation mode. .
3A is a diagram schematically illustrating a state in which the active pen PEN approaches any one electrode included in the panel. 3B is a diagram schematically illustrating a state in which the active pen PEN is detected by different electrodes included in the panel.
4 is a diagram showing an outline of the active pen signal detecting apparatus 1 according to the present embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms or words used in the present specification and claims should not be construed as being limited to conventional or dictionary meanings, and the inventor should properly understand the concept of the term in order to best describe his invention. Based on the principle that it can be defined, it should be interpreted as meaning and concept consistent with the technical idea of the present invention. Accordingly, the configuration shown in the embodiments and drawings described in the present specification is only the most preferred embodiment of the present invention and does not represent all of the technical spirit of the present invention, so at the time of the present application, various It should be understood that there may be equivalents and variations.

1 is a diagram illustrating an outline of an active pen (PEN) according to the present embodiment. Referring to FIG. 1 , the active pen PEN includes a tip electrode TIP in contact with the panel of the active pen signal detection device, a ring electrode RING and an active pen PEN spaced apart from and insulated from the tip electrode TIP. and a tail electrode TAIL positioned in a direction opposite to the tip electrode TIP in the longitudinal direction of the . The tip electrode TIP provides a tip signal TIP_SIGNAL, the ring electrode RING provides a ring signal RING_SIGNAL, and the tail electrode TAIL provides a TAIL Signal signal of the active pen. do.

2(a) to 2(b) are diagrams illustrating the operation mode of the active pen PEN and signals provided by the tip electrode TIP, the ring electrode RING, and the tail electrode TAIL for each operation mode. . FIG. 2A is a diagram illustrating a signal when the active pen PEN is in a front hover mode. Referring to FIG. 2A , in the front hover mode, the tip electrode TIP floats without contacting the panel of the active pen.

In the front hover mode, the tip electrode TIP is a beacon signal (BEACON LF), a digital signal including digital information (DIGITAL LF), a port type (Port Type HF), a digital signal (DIGITAL HF), and a pen pressure A pressure LF signal having information and a beacon HF signal are sequentially output. In addition, in the front hover mode, the tip electrode TIP outputs a signal in units of one frame starting with the beacon signal BEACON LF and ending with the beacon HF signal, and the beacon at the start of the frame. The frequency of the signal BEACON LF and the beacon signal BEACON HF at the end of the frame may be different from each other.

Meanwhile, in the front hover mode, the ring electrode RING may output a signal in synchronization with a high frequency port type HF signal output by the tip electrode TIP.

Figure 2(b) shows the shape of the signal provided by the tip electrode (TIP) and the ring electrode (RING) in the Front Ink mode in which the tip electrode (TIP) of the active pen (PEN) is in contact with the panel. It is the drawing shown. Referring to Figure 2 (b), the signal provided by the tip electrode (TIP) in the front ink (Front Ink) mode is provided by the tip electrode (TIP) in the front hover (Front Hover) mode illustrated in Figure 2 (a) There is a difference in that there is no digital signal (Digital HF) signal in the signal. However, in the Front Ink mode, the ring electrode (RING) provides a beacon signal (BEACON LF), a port type signal (Port Type), a pressure signal (Pressure) and a beacon signal (BEACON HF) provided by the tip electrode (TIP). ) and output a signal in synchronization with the start of

Accordingly, in the front ink mode of the active pen PEN, the electrodes included in the panel in contact with the tip electrode TIP receive both the signal provided from the tip electrode TIP and the signal provided from the ring electrode RING. do. In the illustrated example of the signal, the pressure signal is a signal detected by how much the tip electrode is pressed against the panel. Accordingly, the active pen signal detecting apparatus may obtain information about the pen pressure by detecting the pressure signal.

FIG. 2(c) is a diagram illustrating the shape of a signal provided by the tail electrode TAIL in the tail hover mode in the active pen PEN, in which the tail electrode TAIL does not contact the panel and floats. to be. Referring to FIG. 2C , in a tail hover mode, the tail electrode TAIL outputs a beacon signal BEACON LF and a continuous digital signal DIGITAL LF.

FIG. 2( d ) is a diagram illustrating the shape of a signal provided by the tail electrode TAIL in a tail erase mode in a state in which the tail electrode TAIL is in contact with the panel in the active pen PEN. Referring to FIG. 2( d ), in the tail erase mode, the tail electrode TAIL outputs a beacon signal BEACON LF and a continuous digital signal DIGITAL LF and outputs a pressure signal PRESSURE LF. do. The front hover mode corresponds to a case in which the user approaches the active pen signal detection device to the active pen signal detection device, and the front ink mode allows the user to connect the active pen signal detection device to the active pen signal detection device. It is a mode corresponding to the case of forming a trajectory by touching PEN) to make a dot or write a note.

The tail hover mode corresponds to a case in which the user approaches the tail electrode located in the opposite direction to the tip electrode TIP to the active pen signal detection device, and the tail erase mode is This mode corresponds to a case in which a user touches the tail electrode TAIL to the active pen signal detecting apparatus to form a trajectory. In an embodiment, the tail erase mode may correspond to a mode in which contents formed according to the trajectory of the tip electrode TIP are erased according to the trajectory formed by the tail electrode TAIL.

3A is a diagram schematically illustrating a state in which the active pen PEN approaches any one electrode included in the panel. Referring to FIG. 3A , when a user approaches the panel to write on the panel using an active pen (PEN), a capacitor (C _TIP ) is formed by the tip electrode (TIP) and the electrode included in the panel. and a capacitor (C _RING ) is formed by the ring electrode (RING) and the corresponding electrode, and the two capacitors are equivalent to being connected in parallel to each other. The electrode also forms a capacitor C _D inside the panel.

When the tip electrode (TIP) outputs a Sig _TIP signal having a frequency f1, and the ring electrode (RING) outputs a Sig _RING signal of a frequency f2, the signal SigOUT formed on the electrode and detected is a capacitor C _TIP and a capacitor C _RING and a capacitor It is a signal distributed by C _D , and is expressed in Equation 1 below.

That is, the signal detectable by the electrode is a signal in which the tip signal (SIG _TIP ) provided by the tip electrode (TIP) is distributed according to the capacitance ratio, and the ring signal (SIG _RING ) provided by the ring electrode (RING) is the capacitance It corresponds to the sum of the signals distributed according to the ratio. Accordingly, the detected signal SIG _OUT is expressed as the sum of a component formed by the tip signal and including f1 which is a tip signal frequency component, and a component formed by the ring signal and including f2 which is a frequency component of the ring signal.

In addition, as the active pen is tilted with respect to the panel, the ring electrode RING approaches the electrode, so that a component due to the ring signal in the detected signal Sig _OUT increases. Therefore, when both the magnitude of the tip signal and the magnitude of the ring signal are known, the active pen is displayed on the panel to some extent by calculating the ratio of the component formed by the tip signal to the component formed by the ring signal in the detected signal Sig _OUT . It can be determined whether it is located at the slope of .

3B is a diagram schematically illustrating a state in which the active pen PEN is detected by different electrodes included in the panel. Referring to FIG. 3B , since the tip electrode TIP is closest to the center electrode, the capacitance of the capacitor C _TIP2 formed in the relationship between the tip electrode TIP and the center electrode is formed between two electrodes having different capacitances. It is large compared to the capacitance of capacitors C _TIP1 and C _TIP3 . Similar to the relationship between the ring electrode RING and the other three electrodes in the panel, the capacitance of the capacitor formed with the ring electrode RING and the center electrode is larger than the capacitances of the capacitor formed with the other two adjacent electrodes.

Therefore, the closer the tip electrode TIP and the ring signal RING_SIGNAL, the larger the signal is formed and detectable. Accordingly, the touch position of the tip electrode TIP of the active pen PEN may be obtained by detecting signals formed from three different electrodes and performing an interpolation operation based on the magnitudes.

4 is a diagram illustrating an outline of the active pen signal detecting apparatus 1 according to the present embodiment, and FIG. 5 is a diagram illustrating an outline of the sensing circuit unit 200 according to the present embodiment. 4 and 5 , in the active pen sensing apparatus 10 according to the present embodiment, a panel 100 including a plurality of unit sensor electrodes and a row R of the plurality of unit sensor electrodes Alternatively, the sensor electrode control unit 210 that forms a sensing channel by connecting to a column C and forms a reference signal group REF, and the signal formed in the sensing channel and the signal formed in the reference signal group are in phase ( common mode) and a differential amplifier circuit unit 220 including a differential amplifier for removing the component, and a sensing circuit unit 200 including a detection unit 230 for detecting an active pen signal from the output signal of the differential amplifier.

6 (a) is a view showing a state in which the unit sensor electrodes (TP) are connected in a column by the sensor electrode control unit 210 to form a sensing channel (C), Figure 6 (b) is a unit sensor electrode (TP) ) are connected in a row by the sensor electrode control unit 210 to form a sensing channel (R). 4 to 6 , the sensor electrode controller 210 receives a signal detected by a plurality of unit electrodes TP disposed in the same column in the panel 100 and a signal provided by the selected unit electrode TP. to output For example, the sensor electrode controller 210 may be a multiplexor.

As illustrated in FIG. 6A , the sensor electrode controller 210 may electrically connect the unit electrodes TP positioned in the same column of the panel 100 to each other to form a sensing channel C connected in a column. In addition, the sensor electrode controller 210 electrically connects the unit electrodes TP positioned in the same row in the panel 100 to each other as illustrated in FIG. 6(b) to form a sensing channel R connected in a row. can do. In the sensing channel R connected in a row, a plurality of unit sensor electrodes may be connected in the row by the plurality of sensor electrode controllers 210 .

The sensor electrode controller 210 improves the sensing sensitivity of the active pen by forming sensing channels R and C connecting each of the unit electrodes TP in rows and columns, and performing sensing through the sensing channels R and C. can do it

The sensor electrode controller 210 forms a reference signal group REF by connecting the plurality of unit electrodes TP in a row or column. In an embodiment, the sensor electrode controller 210 connects one or more unit electrodes TP that are spaced apart from the contact point of the active pen PEN and do not participate in the active pen PEN signal in a row or column to connect the reference signal group ( REF) is formed.

In one embodiment, when the sensor electrode controller 210 connects the unit electrodes TP arranged in rows to form the sensing channel R, the sensor electrode controller 210 does not participate in the active pen PEN signal. The reference signal group REFr (refer to FIG. 4 ) may be formed by connecting one or more unit electrodes TP that are not connected in a row. As another example, when the sensor electrode control unit 210 forms a sensing channel C by connecting the unit electrodes TP arranged in a column, the sensor electrode control unit 210 may include one or more active pen PEN signals not participating in the signal. A reference signal group REFc (refer to FIG. 4 ) may be formed by connecting the unit electrodes TP in a column.

In another embodiment, when the sensor electrode controller 210 connects the unit electrodes TP arranged in rows to form the sensing channel R, it connects some of the unit electrodes TP arranged in rows to sense. A reference signal group may be formed by forming the channel R and connecting the unit electrodes TP, which are located in the same row and do not participate in sensing, in a row (see FIG. 8 ). Similarly, when the sensor electrode control unit 210 connects the unit electrodes TP arranged in columns to form the sensing channel C, some of the unit electrodes TP arranged in the column are connected to form the sensing channel C. The reference signal group REF may be formed by connecting the unit electrodes TP located in the same column and not participating in sensing in a column.

6(a) and 6(b), the second resistor R2 represents the line resistance of the fan-out line connected to the detection circuit for detecting the signal provided by the sensing channel, and the first resistor (R1) represents the line resistance from the unit electrode TP in the panel to the fan-out line. Accordingly, in the same panel 100 , the first resistance value of the unit electrode TP connected by the longest wire to the fan-out line is the largest, and the first resistance of the unit electrode TP connected to the fan-out line by the shortest wire in the same panel 100 . value is the smallest. In addition, in the same panel 100 , the second resistance value of the unit electrode TP connected with the longest wire of the fan-out line is the largest, and the second resistance value of the unit electrode TP connected with the shortest wire up to the fan-out line is the second resistance value. 2 The resistance value is the smallest.

The sensing channels C and R formed by connecting the unit electrodes TP in columns or rows detect a signal provided by the active pen and provide it to the differential amplifier circuit unit 220 . In addition, the reference signal group REF formed by connecting the unit electrodes TP in columns or rows detects display noise and provides the detected noise to the differential amplifier circuit unit 220 . The differential amplifier circuit unit 220 includes a differential amplifier, and the differential amplifier may have an inverting input and a non-inverting input, and excludes a common mode component of the input, and a differential (differential mode) The component is amplified and output. Also, the differential amplifier may have an inverting output and a non-inverting output.

Noise, such as display noise, introduced into the panel 100 from the outside of the panel 100 is formed in common not only in the sensing channels R and C in the panel 100 but also in the reference signal group REF. Accordingly, the noise is included as a common mode component in both the signal in which the sensing channels R and C detect the output signal of the active pen PEN and the signal provided by the reference signal group REF.

As described above, the differential amplifier excludes common mode components provided to an inverting input and a non-inverting input. Accordingly, the signal output from the differential amplifier circuit unit 220 is an output signal component of the active pen PEN from which common-mode noise components such as display noise have been removed.

Since noise generated according to the operating environment of the display device can be viewed as a common mode signal as described above, the signal provided by the sensing channels R and C and the reference signal group are provided using the differential amplifier circuit unit. An active pen signal PEN may be detected by comparing one signal REF.

However, as described above in the reference signal group setting, the first resistance (R1, see FIG. 6), which is the line resistance from the unit electrode (TP) in the panel to the fan-out line, and the detection circuit for detecting the signal provided by the sensing channel; A deviation occurs in the characteristic of the second resistor R2 (refer to FIG. 6 ), which is the line resistance of the fan-out line to which it is connected. Such a difference in resistance value prevents removal of the display noise component, so that irregular peaks of the noise signal are formed at the output of the comparator circuit unit 234 , which may frequently cause malfunctions.

7 is a diagram illustrating an outline of the resistance correction circuit unit 240 . 6 and 7 , the resistance compensating circuit unit 240 includes a first compensating unit 212 compensating for the resistance of the sensor electrode control unit 210 and a second compensating unit compensating for the resistance of the reference signal group REF. (214). The first compensating unit 212 includes a plurality of resistors Ra1, Ra2, Ra3, ... and a plurality of switches SWa1, SWa2, SWa3, . ..) is included. The second compensator 214 includes a plurality of resistors Rb1, Rb2, Rb3, ... and a plurality of switches SWb1, SWb2, SWb3, . ..) is included.

In an embodiment, the plurality of resistors Ra1, Ra2, Ra3, ... and the plurality of resistors Rb1, Rb2, Rb3, ... may have different resistance values. , any one of the switches included in the first compensating unit 212 is conductive, and the resistance connected to the conductive switch is connected to the sensor electrode control unit 210 to compensate the resistance, and similarly, to the second compensating unit 214 . Any one of the included resistors may be connected to the reference signal group REF to compensate for the resistance.

As another example, one or more switches included in the first compensating unit 212 may conduct and resistors may be connected in parallel, and parallel-connected resistors may be connected to the sensor electrode control unit 210 to compensate for the resistance. 2 A plurality of resistors included in the compensator 214 may be connected in parallel, and the parallel-connected resistors may be connected to the reference signal group REF to compensate for the resistance.

The compensation resistance calculating unit 510 calculates a resistance value compensated from the resistance characteristics of the row and column of the single sensing channel and the resistance characteristics of the row and column of the reference signal group REF, stores the calculated compensation resistance value, and stores the stored compensation resistance value. to control the resistance correction circuit unit 240 .

In the illustrated embodiment, the compensation resistance calculating unit 510 is exemplified as being located in the processing unit 500 , but in another embodiment not shown, the compensation resistance calculating unit 510 may be located in the sensing circuit unit 200 . In addition, the compensation resistance calculator 510 may include a processor (not shown) capable of performing an operation to be described later and a memory (not shown) for storing the calculated compensation resistance value.

Equation 2 below is an equation for calculating the compensation resistance value of the compensation resistance calculating unit 510 .

Table 1 is a table for explaining that the resistance compensator calculates the compensated resistance value. Referring to Table 1, when the plurality of unit electrodes TP are connected in a column to form the heat sensing channels C, the resistance values up to the unit electrodes TP included in each of the heat sensing channels are calculated and the average is calculated. It is the same as the COL_AVG item in Table 1. It can be seen that the resistance value is the lowest in the fourth column (COL[4]), which is believed to be due to the shortest length of the fan-out line as described above.

REF_CH represents the reference signal group (REF) for the column sensing channel (C), and the reference signal group for the 0th column sensing channel (COL[0]) is set as the 8th column sensing channel (COL[8]) . The reference signal group for the third column sensing channel (COL[3]) was set as the first column sensing channel (COL[1]). However, this is only an example, and the column sensing channel (or row sensing channel) and the reference signal group may be selected differently.

As described above, the reference signal group for the thermal sensing channel does not participate in pen sensing, but may be formed of unit electrodes through which noise of a similar level to that of the thermal sensing channel is introduced.

A difference in resistance between the thermal sensing channel and the reference signal group is calculated, and a compensation value is calculated by dividing by the number of unit electrodes included in the sensing channel. The calculated compensation resistance value may be 0, a negative number, or a positive number. For example, if the value is negative, the resistance value of the heat sensing channel may be increased, and if it is positive, the resistance value connected to the reference signal group may be increased.

The compensation resistance calculating unit 510 stores the calculated compensation resistance value, and outputs a switch control signal to calculate the compensation resistance calculated in the first compensator 212 (refer to FIG. 7 ) and the second compensator 214 (refer to FIG. 7 ). Control the switch to form a value.

Table 1 describes a reference signal group in which a column sensing channel and unit electrodes are connected in a column as an example, but of course, this may also be applied to a reference signal group in which a row sensing channel and unit electrodes are connected in a row.

8 is a diagram illustrating another embodiment of compensating for a resistance deviation. Referring to FIG. 8 , the sensor electrode controller 210 connects four unit electrodes TP in a row to form a row sensing channel R, and connects four other unit electrodes TP belonging to the same row to a row. They can be connected to form a reference signal group REF,r.

Table 2 below is a table for explaining calculation of a compensation resistance value using Equation 2 in the embodiment illustrated in FIG. 8 .

Referring to Table 2, each of the four unit electrodes TP included in the same row is connected as a row group. The resistance values from row group 1 (ROW_GROUP1) to row group 3 (ROW_GROUP3) included in the 0th row (ROW[0]) to the 11th row (ROW[11]) are as shown in Table 2.

In the illustrated embodiment, row group 1 (ROW_GROUP1) is set as the row sensing channel (R), and row group 2 (ROW_GROUP2) in the same row is set as the reference signal group (REF). By calculating the difference in resistance between the row sensing channel and the reference signal group, and dividing the calculated value by 4, which is the number of electrodes included in the row sensing channel R, a compensation resistance value can be obtained as shown.

The compensation resistance value calculated as described above may be 0, negative, or positive. For example, if it is a negative number, the resistance value of the heat sensing channel is increased, and if it is a positive number, the resistance value connected to the reference signal group may be increased. have.

Table 2 describes a reference signal group in which a column sensing channel and unit electrodes are connected in a row as an example, but this may also be applied to a reference signal group in which a column sensing channel and unit electrodes are connected in a column.

The compensation resistance values calculated through the above-described process may be stored in the compensation resistance controller 510 (refer to FIG. 6 ). When pen sensing is performed with the active pen sensing device 10 , the compensation resistance control unit 510 is configured to connect the calculated compensation resistance to the sensing channels R and C or the reference signal group REF according to the sensing channel performing sensing. The switches included in the correction circuit unit 240 are controlled.

The resistance correction circuit unit 240 connects the calculated compensation resistance to the sensing channels R and C or the reference signal group REF, and differentially amplifies the output signal of the sensing channels R and C or the reference signal group REF. provided to the circuit unit 220 .

Signals output from the sensing channels R and C and the reference signal group REF are provided to the differential amplification circuit unit 220 through a resistance-compensated line. Since the differential amplifying circuit unit 220 amplifies and outputs the active pen signal, which is a differential signal component, by excluding noise, which is an in-phase component, from the provided signal, a non-ideal peak may be prevented from being formed in the output of the comparator circuit unit 234 .

The output signal of the differential amplifier circuit unit 220 is provided to the detection unit 230 , and the output signal of the active pen PEN is detected. In one embodiment, the output signal of the differential amplifier circuitry 220 is provided to the comparator circuitry 232 . The comparator circuit unit 232 includes a comparator that compares the reference voltage and the magnitude of the output signal of the differential amplifier circuit unit 220 . The comparator outputs a pulse corresponding to the comparison result. Since the signal output by the active pen PEN is a pulse signal having a predetermined frequency, the pulse signal output by the comparator circuit unit 232 is also a pulse signal corresponding to the frequency of the signal output by the active pen.

Accordingly, the frequency can be determined by counting the pulses included in the pulse signal, and when the symbol frequency of the pen is identical to the predetermined symbol frequency, the active pen signal detecting apparatus 10 can determine that the signal provided by the active pen PEN is detected. have.

As described above, the differential amplifier may include two outputs, each outputting an inverted output signal. Each output of the differential amplifier may be provided to two comparators, each of which may output a pulse.

The output signal of the differential amplifier circuit part 220 is provided to the sampling part 231 . The sampling unit 231 samples the output signal of the differential amplifier circuit unit 220 and outputs the sampled code to the processing unit 500 .

Although it has been described with reference to the embodiment shown in the drawings in order to help the understanding of the present invention, this is an embodiment for implementation, it is merely an example, and various modifications and equivalents from those of ordinary skill in the art It will be appreciated that other embodiments are possible. Accordingly, the true technical protection scope of the present invention should be defined by the appended claims.

PEN: active pen TAIL: tail electrode
RING: ring electrode TIP: tip electrode
10: active pen sensing device 100: panel
200: sensing circuit unit 210: sensor electrode control unit
212: first compensation unit 214: second compensation unit
220: differential amplification circuit unit 230: detection unit
232: sampling unit 234: comparator circuit unit
240: resistance correction circuit unit 500: processing unit
510: compensating resistance calculation unit

Claims (11)

A panel including a plurality of unit sensor electrodes, and
a sensor electrode controller connecting the plurality of unit sensor electrodes in a row or column to form a sensing channel and forming a reference signal group;
a differential amplifier circuit unit including a differential amplifier for removing a common mode component from a signal detected from the sensing channel and a signal formed from the reference signal group;
a detector for detecting an active pen signal from the output signal of the differential amplifier;
a resistance correction circuit unit for matching the resistance of the sensing channel viewed from the differential amplifier and the resistance of the reference signal group viewed from the differential amplifier;
The resistance correction circuit unit,
a first compensator connected between one input of the differential amplifier and the sensing channel, the first compensating unit including a plurality of switches conducting with a plurality of resistors to connect the plurality of resistors with the sensing channel;
a second compensator connected between the other input of the differential amplifier and the reference signal group, the second compensator including a plurality of switches which are conductive to a plurality of resistors and connect the plurality of resistors to the reference signal group;
and a compensation resistance calculator controlling resistances of the first compensator and the second compensator, respectively.
According to claim 1,
The frostbite component is
Active pen sensing device, which is display noise.
According to claim 1,
The sensor electrode control unit,
An active pen sensing device connected to the plurality of unit sensor electrodes disposed in the same column of the panel.
According to claim 1,
The active pen sensing device,
It includes a plurality of the sensor electrode control unit,
The plurality of unit sensor electrodes are connected in the row by the plurality of sensor electrode controllers.
According to claim 1,
The sensing channel is two or more unit sensor electrodes connected in a row,
The reference signal group is two or more unit sensor electrodes adjacent to or spaced apart from the sensing channel and connected in a row.
According to claim 1,
The sensing channel is two or more unit sensor electrodes connected in a column,
The reference signal group is two or more unit sensor electrodes adjacent to or spaced apart from the sensing channel and connected in a row.
According to claim 1,
The detection unit,
a comparator for outputting a pulse obtained by comparing the magnitude of the output signal of the differential amplifier circuit with a reference level;
The active pen sensing device further comprising a sampling circuit for sampling the output signal of the differential amplifier circuit unit.
delete delete delete According to claim 1,
The compensation resistance calculating unit,
An active pen sensing device for calculating a compensation resistance by dividing a difference between the average resistance value of the sensing channel and the average resistance value of the reference signal group by the number of unit sensor electrodes included in the sensing channel.

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