CN106843545A - Active stylus and control method thereof - Google Patents

Abstract

The present invention provides an active stylus and a control method thereof, which are applicable to a touch panel. The touch panel includes a plurality of driving electrodes and a plurality of sensing electrodes, each driving electrode is used to send a panel driving signal, and the sensing electrode is used to receive the panel driving signal. The active stylus includes a receiving element for receiving the panel driving signal, a sensing module for obtaining the signal characteristics of the panel driving signal, a signal generator for generating an analog driving signal, a driving element for sending the analog driving signal, and a control unit. The control unit generates an analog driving signal that is synchronized and in phase with the panel driving signal through the signal generator according to the signal characteristics of the panel driving signal. Thereby, in the mutual capacitance mode, the touch panel can achieve the functions of multi-touch and distinguishing between the hand and the active stylus.

Description

Active stylus and control method thereof

technical field

The invention relates to a touch pen, in particular to an active touch pen.

Background technique

Currently, the mainstream projected capacitive touch panel is a mutual capacitive structure. These touch panels are usually provided with a plurality of driving electrodes and a plurality of sensing electrodes, and the driving and sensing electrodes are arranged vertically and alternately. The junctions of these driving and sensing electrodes form sensing capacitances. When a finger touches the touch panel, the corresponding sensing capacitance changes, and the touch panel can obtain the touch position of the finger.

On the other hand, a stylus is an auxiliary tool commonly used to assist users in writing or drawing on a touch panel. The stylus on the market can be roughly classified into two types: passive and active. The main difference is that the active stylus can send driving signals to be sensed by the sensing electrodes of the touch panel, but the passive stylus does not send driving signals. Signal. However, the existing active stylus usually sends a driving signal simulating a finger to change the sensing capacitance in the touch panel, but the control chip of the touch panel cannot distinguish the difference between the active stylus or hand contact. Although some manufacturers have launched touch panels with switchable modes, when the touch panel is in self-capacitance mode (all electrodes (including drive electrodes) are switched to sensing electrodes), the control crystal can distinguish between active stylus or The difference in hand contact, but this touch panel can only support single touch. It can be seen that how to provide an active stylus that can enable the touch panel to realize the functions of multi-touch and distinguishing hand touch is one of the goals of the related industry.

Contents of the invention

In view of this, the object of the present invention is to provide an active stylus and its control method, so that a touch panel can distinguish the active stylus and the touch of the hand and also support multi-touch.

To achieve the above purpose, the present invention provides an active stylus suitable for a touch panel. The touch panel includes a plurality of driving electrodes and a plurality of sensing electrodes, each of the driving electrodes is used for sending a panel driving signal, and the sensing electrodes are used for receiving the panel driving signal. The active touch pen includes a receiving element, a sensing module, a signal generator, a driving element and a control unit. The receiving element is used for receiving the panel driving signal. The sensing module is coupled to the receiving element and used for obtaining the signal characteristic of the panel driving signal in response to the panel driving signal. The signal generator is used for generating an analog driving signal. The driving element is coupled to the signal generator and used for sending the analog driving signal. The control unit is coupled to the sensing module and the signal generator, and generates the analog driving signal synchronously and in phase with the panel driving signal through the signal generator according to the signal characteristics of the panel driving signal.

The present invention also provides a control method for an active stylus, the active stylus is suitable for a touch panel, the touch panel includes a plurality of driving electrodes and a plurality of sensing electrodes, each of the driving electrodes is used for To send a panel driving signal, the sensing electrodes are used to receive the panel driving signal, and the control method includes the following steps. Receive the panel drive signal. The signal characteristic of the panel driving signal is obtained. The analog driving signal which is synchronous and in phase with the panel driving signal is generated according to the signal characteristic of the panel driving signal. Send the analog drive signal.

Since the sensing signal of a finger sensed by the sensing electrodes is out of phase with the panel driving signal, when the finger and the active stylus touch the touch panel, the corresponding sensing electrodes will sense two signals with different phases. sensing value, thereby distinguishing the finger or the active stylus. In addition, the touch panel can maintain the mutual capacitance mode (without switching the driving electrodes into the sensing electrodes) to realize most of the input control of the active stylus.

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments, but not as a limitation of the present invention.

Description of drawings

FIG. 1 is a block diagram of components of an active stylus according to a preferred embodiment of the present invention.

FIG. 2 is a schematic diagram of a touch panel.

FIG. 3 is a flowchart of a method for controlling an active stylus according to a preferred embodiment of the present invention.

FIG. 4A is an example of a waveform diagram of a panel driving signal sent by the driving electrodes.

FIG. 4B is an example of a waveform diagram of the signal strength sensed by the capacitive sensor.

FIG. 4C is an example of a waveform diagram of an analog driving signal.

FIG. 5 is a schematic diagram of writing and an example of a corresponding sensing waveform diagram.

Among them, reference signs

1 active stylus 5 hands

10 receiving elements

20 Sensing module 21 Capacitive sensor 23 Amplifying circuit

30 signal generator 40 drive element 50 control unit

51,53 signal strength

60 touch panel 61 driving electrode 63 sensing electrode

Steps S31 to S37

A1, A2, A3 amplitude value D duty cycle f frequency

SC control signal SC control signal SD analog drive signal

SO output signal SP panel drive signal SS signal strength

detailed description

The technical solution of the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments to further understand the purpose, solution and effect of the present invention, but it is not intended to limit the scope of protection of the appended claims of the present invention.

Please refer to FIG. 1 , which is a block diagram of components of an active stylus 1 according to a preferred embodiment of the present invention. The active stylus 1 includes a receiving element 10 , a sensing module 20 , a signal generator 30 , a driving element 40 and a control unit 50 . The active stylus 1 is suitable for a capacitive touch panel 60, please refer to FIG. 2, the touch panel 60 includes a plurality of driving electrodes 61 and a plurality of sensing electrodes 63 ( That is, mutual capacitance structure), each of the driving electrodes 61 is used to send a panel driving signal SP, and the sensing electrodes 63 are used to receive the panel driving signal SP.

It should be noted that the number of these driving and sensing electrodes 61, 63 shown in FIG. 2 is only for convenience of description, and according to different design requirements, in other embodiments, these driving and sensing electrodes 61, 63 may have different numbers .

The receiving element 10 can be an element made of any conductive material (eg, metal, metal oxide, graphene, etc.) that can accept (sense) the panel driving signal SP. The receiving element 10 is used for receiving the panel driving signal SP.

The sensing module 20 is coupled to the receiving element 10 and used for obtaining signal characteristics (eg, signal strength, peak value, valley value, frequency, etc.) of the panel driving signal SP. The sensing module 20 includes a capacitive sensor 21 and an amplifying circuit 23 . The capacitive sensor 21 responds to the panel driving signal SP to obtain a corresponding signal strength SS (ie, amplitude value or sensing value), and the amplifying circuit 23 responds to the panel driving signal SP to output an output signal SO. In this embodiment, the amplifying circuit 23 is a comparator, and the panel driving signal SP and a reference signal (related to the peak value of the panel driving signal SP) are input to the comparator, if the signal of the panel driving signal SP If the strength is greater than the signal strength of the reference signal, the comparator outputs, for example, a high potential output signal SO; otherwise, the comparator outputs a low potential output signal SO.

It should be noted that, according to different design requirements, the capacitive sensor 21 and the amplifier circuit 23 can be integrated into a module, chip or circuit, but in other embodiments, the two can be independent units.

The signal generator 30 can receive a control signal SC and generate a corresponding analog driving signal SD according to the control signal SC. The control signal SC is used to indicate the signal characteristic of the analog driving signal SD, and in this embodiment, the signal characteristic of the analog driving signal SD includes at least one of a duty cycle and an amplitude value, and analog timing information (for example, the starting time point, period or frequency of each period, etc.).

The driving element 40 is made of the same or similar conductive material as the receiving element 10 . The driving element 40 is coupled to the signal generator 30 and used for sending the analog driving signal SD.

The control unit 50 may be a microcontroller, a chip, or other programmable general-purpose or special-purpose controllers, or a combination thereof. The control unit 50 is coupled to the capacitive sensor 21 and the amplifying circuit 23 of the sensing module 20, and the signal generator 30, the control unit 50 can receive the signal strength SS and the output signal SO, and the control unit 50 can also It has the functions of timing (such as built-in clock generator, oscillator, etc.), calculation, recording, etc. to send the control signal SC to the signal generator 30 .

The foregoing description is related to the component design of the active stylus 1 , and the control method of the active stylus 1 will be further described below with reference to FIGS. 3 , 4A to 4C .

Please refer to FIG. 4A , which is an example waveform diagram of the panel driving signal SP sent by one of the driving electrodes 61 . The panel driving signal SP is a pulse wave signal with an amplitude value A1 and a frequency f. Referring to FIG. 3, when the active stylus 1 is close to a certain distance (for example, about 0.5-1 cm) from the touch panel 60, the receiving element 10 can receive the panel driving signal SP ( Step S31).

In step S33 , the sensing module 20 obtains the signal characteristic of the panel driving signal SP. Please refer to FIG. 4B , which is an example waveform diagram of the signal strength SS sensed by the capacitive sensor 21 . The capacitive sensor 21 senses a signal with an amplitude value A2 and a frequency f. The capacitive sensor 21 obtains the signal strength SS of the panel driving signal SP sensed by it.

In this embodiment, after the control unit 50 obtains the signal strength SS of the panel driving signal SP, in order to reflect the distance between the active stylus 1 and the touch panel 60, the control unit 50 according to the signal strength SS The signal characteristics of the analog drive signal SD are determined. In this embodiment, the signal characteristics of the analog driving signal SD are a duty ratio D and an amplitude value A3. Please refer to the following table (1) for the signal characteristics of the analog drive signal SD:

Table 1)

Frequency f(kHz) Duty cycle D Amplitude value A3 (volts) signal strength 100 50% 5 -20 100 50% 10 -40 100 25% 5 -10 100 25% 10 -20 100 75% 5 -30 100 75% 10 -60

Since the signal intensity of the panel driving signal SP sensed by the capacitive sensor 21 is related to the distance between the active stylus 1 and the touch panel 60, the signal characteristic of the analog driving signal SD is also related to the distance between the active stylus 1 and the touch panel 60. The signal strength of the panel driving signal SP changes. Wherein, the product of the duty cycle D and the amplitude value A3 is related to the signal strength SS sensed by the capacitive sensor 21 .

It should be noted that the combination of pulse width and pulse amplitude modulation (PWM) and PAM in this embodiment is only used for illustration; in other embodiments, according to the design requirements of different touch panels, the panel driving signal SP may be different or modulation coding, and the analog driving signal SD needs to change with the signal characteristics of the panel driving signal SP.

On the other hand, the amplifying circuit 23 outputs an output signal SO according to the signal strength of the panel driving signal SP. The control unit 50 obtains two adjacent peak values of the panel driving signal SP according to the output signal SO of the amplifying circuit 23. For example, the control unit 50 judges that the output signal SO is changed from a low potential to a high potential, and the control unit 50 and Calculate the time difference between the two adjacent peaks to obtain the frequency (the reciprocal of the time difference is the frequency f of the panel driving signal SP). The control unit 50 can determine the analog timing information of the analog driving signal SD according to the panel timing information. In this embodiment, the frequency f of the panel driving signal SP is equal to the frequency f of the analog driving signal SD. In addition, the control unit 50 can estimate the start time point of each period of the panel driving signal SP to synchronize the panel driving signal SP with the analog driving signal SD.

It should be noted that there are many ways to calculate the frequency or period of the signal. For example, the amplifying circuit 23 is an operational amplifier, and the control unit 50 can obtain a peak value and an adjacent valley of the panel driving signal SP. value, the frequency can also be deduced according to the time difference between the peak value and the valley value; or, the control unit 50 calculates the time difference between two adjacent valley values.

In step S35, the control unit 50 is used to indicate the signal characteristics of the analog driving signal SD according to the signal characteristics of the panel driving signal SP (ie frequency f, amplitude value A3, duty cycle D, The control signal SC at the starting time point) is transmitted to the signal generator 30 to control the signal generator 30 to generate an analog driving signal SD synchronous with the panel driving signal SP (that is, the frequency and the starting time point are consistent) (as shown in FIG. 4C), the signal generator 30 and the analog drive signal SD and the panel drive signal SP in phase (refer to Figures 4A and 4C at the same time). In step S37, the driving element 40 can send the analog driving signal SD.

Please refer to FIG. 5, when a hand 5 touches the touch panel 60 with the active stylus 1, the analog drive signal SD sent by the active stylus 1 is in phase with the panel drive signal SP, then the touch The panel 60 will sense a negative signal strength 51; and the capacitance change caused by the hand 5 will cause the touch panel 60 to sense a positive signal strength 53, thereby distinguishing the active stylus 1 and The touch of the hand 5. That is to say, in the mutual capacitance mode (that is, the driving electrodes still send the panel driving signal SP), the touch panel 60 can still recognize the active stylus 1 and the hand 5, and then can filter the hand. 5 sensing signals to achieve anti-touch writing function. In addition, in the mutual capacitance mode, when two or more active stylus 1 approach the touch panel 60 at the same time, the touch panel 60 can sequentially sense capacitance changes through the sensing electrodes 63, thereby The sensing positions of the active stylus 1 are obtained, and no ghost point will occur.

On the other hand, the signal characteristic of the analog driving signal SD is related to the signal strength SS obtained by the capacitive sensor 21 (that is, related to the distance between the active stylus 1 and the touch panel 60). The panel 60 can judge the distance between the active stylus 1 and the touch panel 60 according to the signal strength sensed in response to the analog driving signal SD, and then simulate the change of stroke weight or other stroke conditions. It should be noted that the control unit 50 can also fix the duty cycle D and the amplitude value A3 of the analog driving signal SD, and still achieve the function of distinguishing the active stylus 1 from the hand 5 and multi-touch .

Certainly, the present invention also can have other multiple embodiments, without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and deformations according to the present invention, but these corresponding Changes and deformations should belong to the scope of protection of the appended claims of the present invention.

Claims (10)

1. a kind of active stylus, it is characterised in that suitable for a contact panel, the contact panel includes and multiple drives electricity Pole and multiple induction electrodes, each driving electrodes are used to send a panel drive signal, and those induction electrodes are used to receive this Panel driving signal, and the active stylus includes：

One receiving element, is used to receive the panel driving signal；

One sensing module, couples the receiving element, and the sensing module is used to react on the panel driving signal and draw the panel The characteristics of signals of drive signal；

One signal generator, is used to produce an analog drive signal；

One driving element, couples the signal generator, and the driving element is used to send the analog drive signal；And

One control unit, couples the sensing module and the signal generator, the control unit according to the panel driving signal letter Number characteristic and pass through the signal generator and produce the analog drive signal synchronous with the panel driving signal and with phase.

2. active stylus as claimed in claim 1, it is characterised in that the characteristics of signals of the panel driving signal includes One signal intensity, the sensing module includes a capacitance sensor and couples the receiving element and the control unit, the capacitance sensing Device reacts on the panel driving signal and draws corresponding signal intensity, and the control unit determines the mould according to the signal intensity Intend the characteristics of signals of drive signal.

3. active stylus as claimed in claim 1, it is characterised in that the analog drive signal is a pulse wave signal, and The characteristics of signals of the analog drive signal includes an a duty when amplitude at least one of which.

4. active stylus as claimed in claim 1, it is characterised in that the characteristics of signals of the panel driving signal includes One panel timing information, the characteristics of signals of the analog drive signal includes a simulated timing diagrams information, and the sensing module includes One amplifying circuit couples the receiving element and the control unit, and the amplifying circuit reacts on the panel driving signal and to export one defeated Go out signal, interrogated when the control unit draws the panel timing information, and the control unit according to the panel according to the output signal Information determines the simulated timing diagrams information of the analog drive signal.

5. active stylus as claimed in claim 4, it is characterised in that the timing information is a frequency, and the control list Unit draws two adjacent peaks of the panel driving signal according to the output signal, and the control unit simultaneously calculates two adjacent peak Time difference is drawing the frequency.

6. a kind of control method of active stylus, it is characterised in that the active stylus is applied to a contact panel, should Contact panel includes multiple driving electrodes and multiple induction electrodes, and each driving electrodes are used to send panel driving letter Number, those induction electrodes are used to receive the panel driving signal, and the control method includes：

Receive the panel driving signal；

Obtain the characteristics of signals of the panel driving signal；

The analog-driven synchronous with the panel driving signal and with phase is produced according to the characteristics of signals of the panel driving signal Signal；And

Send the analog drive signal.

7. the control method of active stylus as claimed in claim 6, it is characterised in that the signal of the panel driving signal Characteristic includes a signal intensity, and includes the step of obtain the characteristics of signals of the panel driving signal：

React on the panel driving signal and draw corresponding signal intensity；And

The characteristics of signals of the analog drive signal is determined according to the signal intensity.

8. the control method of active stylus as claimed in claim 7, it is characterised in that the analog drive signal is an arteries and veins Ripple signal, and the characteristics of signals of the analog drive signal includes an a duty when amplitude at least one of which.

9. the control method of active stylus as claimed in claim 6, it is characterised in that the signal of the panel driving signal Characteristic includes a panel timing information, and the characteristics of signals of the analog drive signal includes a simulated timing diagrams information, and obtains The step of characteristics of signals for going out the panel driving signal, includes：

The panel timing information is drawn according to the panel driving signal；And

The simulated timing diagrams information that information determines the analog drive signal is interrogated during according to the panel.

10. the control method of active stylus as claimed in claim 9, it is characterised in that the timing information is a frequency, And include the step of draw the panel timing information according to the panel driving signal：

Determine two adjacent peaks of the panel driving signal；And

The time difference of two adjacent peak is calculated to draw the frequency.