CN109271051B

CN109271051B - Capacitive touch system and sensing method thereof

Info

Publication number: CN109271051B
Application number: CN201710580107.1A
Authority: CN
Inventors: 郭锦华; 游薪轩; 叶骏颖; 叶映志
Original assignee: Silicon Integrated Systems Corp
Current assignee: Silicon Integrated Systems Corp
Priority date: 2017-07-17
Filing date: 2017-07-17
Publication date: 2021-09-28
Anticipated expiration: 2037-07-17
Also published as: CN109271051A

Abstract

The disclosure relates to a capacitive touch system and a sensing method thereof, wherein the capacitive touch system comprises a touch panel; a touch control chip; and an active pen including a receiving portion, a transmitting portion, a control unit, and a pressure sensing assembly. The control unit controls the sending part to output a driving signal according to a pen sensing signal. The pressure sensing component detects a pressure signal, and the control unit responds to the pressure signal and outputs a voltage signal after delaying for a period. In the capacitive touch system and the sensing method thereof, the active pen and the touch panel do not need to be paired online.

Description

Capacitive touch system and sensing method thereof

Technical Field

The present disclosure relates to touch technologies, and more particularly, to a capacitive touch system and a sensing method thereof.

Background

With the development of Touch Panels (TP), the peripheral products of Touch panels are being developed, and the active pen (active pen) is one of the peripheral products. Currently, an active pen has a pressure sensing function, and a pressure sensing value sensed by the active pen is transmitted to a touch panel through bluetooth or other wireless communication standards, however, before the active pen transmits the sensed pressure sensing value to the touch panel, the active pen must be paired with the touch panel on line, which makes the active pen inconvenient to use.

There is therefore a need to provide a solution to the above-mentioned problems of the prior art.

Disclosure of Invention

The present disclosure provides a capacitive touch system and a sensing method thereof, which can solve the problems in the prior art.

The capacitive touch system of the present disclosure includes a touch panel; a touch control chip for periodically outputting a panel driving signal to the touch control panel; and an active pen including a receiving portion, a transmitting portion, a control unit, and a pressure sensing assembly. The receiving part senses the panel driving signal and generates a pen sensing signal, the control unit controls the sending part to output a pen driving signal according to the pen sensing signal, and the touch control chip detects the touch position of one of the active pens according to the pen driving signal. The pressure sensing component detects a pressure signal according to the touch and transmits the pressure signal to the control unit, the control unit responds to the pressure signal and outputs a voltage signal after delaying for a period, and the voltage signal is transmitted to the touch chip through the transmitting part and the touch panel.

In the sensing method of the capacitive touch system of the present disclosure, the capacitive touch system includes a touch panel, a touch chip, and an active pen, the active pen includes a receiving portion, a transmitting portion, a control unit, and a pressure sensing device, the sensing method of the capacitive touch system includes the receiving portion sensing the panel driving signal and generating a pen sensing signal; the control unit controls the sending part to output a driving signal according to the pen sensing signal; the touch control chip detects a touch position of the active pen according to the pen driving signal; the pressure sensing assembly detects a pen pressure signal according to the touch and transmits the pen pressure signal to the control unit; the control unit responds to the pen pressure signal and outputs a voltage signal after delaying for a period; and the voltage signal is transmitted to the touch chip through the transmitting part and the touch panel.

In the capacitive touch system and the sensing method thereof, the active pen and the touch panel do not need to be paired online. Furthermore, the active pen may transmit pen driving signals (for detecting the location of a touch) synchronously and voltage signals (for detecting a pressure sensing value) asynchronously.

In order to make the aforementioned and other aspects of the present disclosure more comprehensible, preferred embodiments accompanied with figures are described in detail below:

drawings

Fig. 1 shows a schematic diagram of a touch panel.

Fig. 2 shows a schematic diagram of a coupling capacitor formed between a driving electrode and a sensing electrode of the touch panel.

FIG. 3 is a schematic diagram showing the relationship between the coupling capacitance and a ground capacitance of the touch panel.

Fig. 4 shows a schematic diagram of a panel driving signal and a sensing signal measured when no finger is approached.

FIG. 5 shows a schematic diagram of panel driving signals and sensing signals measured when a finger is in proximity.

Fig. 6 shows a schematic diagram of an active pen.

FIG. 7 is a schematic diagram of a capacitive touch system according to an embodiment of the disclosure.

FIG. 8 is a waveform diagram of a capacitive touch system detecting a touch position and a pen pressure signal according to an embodiment of the disclosure.

FIG. 9 is a flowchart illustrating a sensing method of a capacitive touch system according to an embodiment of the present disclosure.

Detailed Description

In order to make the objects, technical solutions and effects of the present disclosure clearer and clearer, the present disclosure is further described in detail below with reference to the drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the disclosure and that the word "embodiment" as used in this disclosure is intended to serve as an example, instance, or illustration and is not intended to limit the disclosure. In addition, the articles "a" and "an" as used in this disclosure and the appended claims may generally be construed to mean "one or more" unless specified otherwise or clear from context to be directed to a singular form. Also, in the drawings, elements having similar or identical structures, functions, and the like are referred to by the same element numbers.

Referring to fig. 1, fig. 1 shows a schematic diagram of a touch panel 10. The Touch Panel 10 may be a Capacitive Touch Panel.

As shown in fig. 1, the touch panel 10 generally includes a plurality of electrodes arranged in a matrix and wires connecting the electrodes, the electrodes are made of Indium Tin Oxide (ITO), and the electrodes are usually in the shape of bars (Bar) or diamonds (Diamond). In the Mutual Capacitance (Mutual Capacitance) structure, the electrodes include a plurality of driving electrodes 12 (as shown in fig. 2) and a plurality of sensing electrodes 14 (as shown in fig. 2), and accordingly, the conductive lines also include a plurality of driving conductive lines 16 and a plurality of sensing conductive lines 18, the driving conductive lines 16 are respectively connected to the driving electrodes 12, and the sensing conductive lines 18 are respectively connected to the sensing electrodes 14. The mutual capacitance structure is driven by sequentially applying a Panel driving signal TP _ TX (TP represents Touch Panel) to the driving electrodes 12 through the driving wires 16, the Panel driving signal TP _ TX is usually a pulse signal, and accordingly, sequentially reading sensing signals TP _ RX from the sensing electrodes 14 through the sensing wires 18.

Referring to fig. 1 to 3, fig. 2 shows a schematic diagram of a coupling capacitor Cm formed between a driving electrode 12 and a sensing electrode 14 of the touch panel 10, and fig. 3 shows a schematic diagram of a relationship between the coupling capacitor Cm of the touch panel 10 and a grounding capacitor Cg.

As shown in fig. 1 to 3, a coupling capacitance Cm is formed between the driving electrode 12 and the sensing electrode 14. As shown in fig. 1 and 3, the grounding capacitance Cg is formed between the sensing electrode 14 and a ground 20. When a finger (or the like) approaches, the coupling capacitance Cm changes, thereby changing the sensing signal TP _ RX measured from the sensing electrode 12.

Referring to fig. 1 to 5, fig. 4 shows schematic diagrams of a panel driving signal TP _ TX and a sensing signal TP _ RX measured when no finger is approaching, and fig. 5 shows schematic diagrams of the panel driving signal TP _ TX and the sensing signal TP _ RX measured when the finger is approaching.

As shown in fig. 4 and 5, when a finger approaches, the coupling capacitance Cm between the driving electrode 12 and the sensing electrode 14 in fig. 2 is affected to decrease, so that the sensing signal TP _ RX measured from the sensing electrode 14 through the sensing wire 18 also decreases, the touch chip 22 in fig. 1 sequentially applies the panel driving signal TP _ TX to each driving electrode 12 of the touch panel 10 and sequentially reads the sensing signal TP _ RX on each sensing electrode 14, so as to resolve the touched position.

Please refer to fig. 6, which is a diagram illustrating the active pen 30. The active pen 30 (also called active stylus or capacitive pen) can generate an effect similar to that of touching the touch panel 10 of fig. 1 with a finger, i.e. change the capacitance of the coupling capacitor Cm between the driving electrode 12 and the sensing electrode 14 of fig. 2. The active pen 30 includes a housing 32, a receiving portion 34, a transmitting portion 36, and a pressure sensing element 38, the housing 32 has a hollow structure, the receiving portion 34 is disposed at an outward extension of one end of the housing 32, the receiving portion 34 is used for receiving the panel driving signal TP _ TX of fig. 1, the transmitting portion 36 is disposed inside the end of the housing 32 and is used for generating a pen driving signal according to the panel driving signal TP _ TX, the pen driving signal is transmitted to the sensing electrode 14 of fig. 2 through the pressure sensing element 38, so as to change a coupling capacitance Cm formed between the driving electrode 12 and the sensing electrode 14 for detection by the touch chip 22 of fig. 1.

In addition, when the pressure sensing element 38 contacts the touch panel 10 of fig. 1, the pressure sensing element 38 detects a pressure signal for the touch chip 22 to obtain a pressure value of the active pen 30 on the touch panel 10.

Referring to fig. 1 to 8, fig. 7 is a schematic diagram illustrating a capacitive touch system according to an embodiment of the disclosure, and fig. 8 is a waveform diagram illustrating a position of a touch 50 and a pen pressure signal detected by the capacitive touch system according to an embodiment of the disclosure.

The capacitive touch system includes the touch panel 10, the touch chip 22, and the active pen 30.

In a position detection mode, the touch chip 22 is electrically connected to the touch panel 10 and is used for periodically outputting the panel driving signal TP _ TX to the touch panel 10, the receiving portion 34 of the active PEN 30 senses the panel driving signal TP _ TX and generates a PEN sensing signal PEN _ RX, a control unit 40 of the active PEN 30 controls the transmitting portion 36 to output a PEN driving signal PEN _ TX (i.e. the signal of the period T1 in fig. 8) according to the magnitude of the PEN sensing signal PEN _ RX, the PEN driving signal PEN _ TX is transmitted to the sensing electrode 14 in fig. 2 through the pressure sensing component 38, so as to change the coupling capacitance Cm formed between the driving electrode 12 and the sensing electrode 14 for the touch chip 22 to detect the position (i.e. the coordinates) of the touch 50 of the active PEN 30.

For example, the PEN driving signal PEN _ TX is proportional to the PEN sensing signal PEN-RX, i.e., the larger the PEN sensing signal PEN-RX is, the larger the PEN driving signal PEN _ TX is, in order to simulate a finger touch, so that the voltage variation shape approximates to a Gaussian curve, so as to calculate the coordinates of the touch 50.

After the position detection mode, the active pen 30 is switched to a pressure detection mode, when the pressure sensing element 38 generates the touch 50 on the touch panel 10, the pressure sensing element 38 detects a pressure signal and transmits the pressure signal to the control unit 40 of the active pen 30, the control unit 40 outputs a voltage signal (i.e. the signal of the period T2 in fig. 8) after delaying for a period in response to the pressure signal, and the voltage signal is transmitted to the touch chip 22 through the transmitting part 36 and the touch panel 10. The delay period (i.e., between the period T1 and the period T2 in fig. 8) is not limited, and may be adjusted or designed according to the driving frequency of the panel driving signal TP _ TX.

In the prior art, the active pen must be paired with the touch panel on-line to transmit the pressure sensing value, and the capacitive touch system of the present disclosure is characterized in that the voltage signal is transmitted through the pressure sensing element 38, so that the active pen 30 and the touch panel 10 do not need to be paired on-line. Furthermore, the period of time during which the control unit delays outputting the voltage signal can be properly designed according to the driving frequency of the panel driving signal TP _ TX, so that the PEN driving signal PEN _ TX can not be affected in the position detection mode, that is, in the position detection mode, the active PEN 30 can synchronously transmit the PEN driving signal PEN _ TX (for detecting the position of a touch), and in the pressure detection mode, the active PEN 30 asynchronously transmits the voltage signal (for detecting a pressure sensing value).

More specifically, after the voltage signal is transmitted to the control unit 40, the control unit 40 converts the voltage signal into analog to digital, and outputs the voltage signal according to the converted value (i.e. representing the magnitude of the voltage signal), wherein the voltage signal may be a square wave or other waveforms, such as a triangular wave, a sawtooth wave, etc.

In one embodiment, the time duration of the voltage signal outputted by the control unit 40 is proportional to the magnitude of the voltage signal, i.e. the larger the voltage signal is, the longer the time duration of the voltage signal is.

In one embodiment, the frequency of the voltage signal is the same as the driving frequency of the panel driving signal TP _ TX. In another embodiment, the frequency of the voltage signal may be different from the driving frequency of the panel driving signal TP _ TX.

Referring to fig. 9, fig. 9 is a flowchart illustrating a sensing method of a capacitive touch system according to an embodiment of the present disclosure.

The capacitive touch system comprises a touch panel, a touch chip and an active pen, wherein the active pen comprises a receiving part, a transmitting part, a control unit and a pressure sensing component, and the sensing method of the capacitive touch system comprises the following operations.

In block S100, the receiving part senses the panel driving signal and generates a pen sensing signal.

In block S102, the control unit controls the sending unit to output a driving signal according to the pen sensing signal. The pen driving signal is proportional to the pen sensing signal.

In block S104, the touch chip detects a touched position of the active pen according to the pen driving signal.

In block S106, the pressure sensing assembly detects a pen pressure signal according to the touch and transmits the pen pressure signal to the control unit. More specifically, after the voltage signal is transmitted to the control unit, the control unit performs analog-to-digital conversion on the voltage signal and outputs the voltage signal according to the converted value.

In block S108, the control unit outputs a voltage signal after delaying for a period in response to the pen voltage signal. The period is adjusted according to the driving frequency of the panel driving signal. The time length of the voltage signal output by the control unit is proportional to the magnitude of the voltage signal. The frequency of the voltage signal is the same as the driving frequency of the panel driving signal.

In block S110, the voltage signal is transmitted to the touch chip through the transmitting portion and the touch panel.

In summary, although the present disclosure has been described with reference to the preferred embodiments, the above-described preferred embodiments are not intended to limit the present disclosure, and those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure, so that the scope of the present disclosure is defined by the appended claims.

Claims

1. A capacitive touch system, comprising:

a touch panel;

a touch control chip for periodically outputting a panel driving signal to the touch control panel; and

an active pen, which comprises a receiving part, a transmitting part, a control unit and a pressure sensing component,

wherein in a position detection mode, the receiving portion senses the panel driving signal and generates a pen sensing signal, the control unit controls the transmitting portion to synchronously output a pen driving signal according to the pen sensing signal, the touch chip detects a touch position of the active pen according to the pen driving signal, the pen driving signal is used for detecting the touch position,

after the position detection mode, the active pen is switched to a pressure detection mode, in the pressure detection mode, the pressure sensing assembly detects a pressure signal according to the touched position and transmits the pressure signal to the control unit, the control unit responds to the pressure signal and outputs a voltage signal after delaying for a period, the voltage signal is asynchronously transmitted to the touch chip through the transmitting part and the touch panel, and the voltage signal is used for detecting a pressure sensing value.

2. The capacitive touch system of claim 1, wherein the pen driving signal is proportional to the pen sensing signal.

3. The capacitive touch system of claim 1, wherein the period is adjusted according to a driving frequency of the panel driving signal.

4. The capacitive touch system of claim 1, wherein after the touch signal is transmitted to the control unit, the control unit performs analog-to-digital conversion on the touch signal and outputs the voltage signal according to the converted value.

5. The capacitive touch system of claim 1, wherein a duration of the control unit outputting the voltage signal is proportional to a magnitude of the voltage signal.

6. The capacitive touch system of claim 1, wherein the voltage signal has a frequency equal to a driving frequency of the panel driving signal.

7. A sensing method of a capacitive touch system, the capacitive touch system comprising a touch panel, a touch chip, and an active pen, the active pen comprising a receiving portion, a transmitting portion, a control unit, and a pressure sensing device, the sensing method of the capacitive touch system comprising:

in a position detection mode, the receiving part senses a panel driving signal and generates a sensing signal;

in the position detection mode, the control unit controls the sending part to synchronously output a driving signal according to the pen sensing signal;

in the position detection mode, the touch control chip detects a touched position of the active pen according to the pen driving signal, and the pen driving signal is used for detecting the touched position;

after the position detection mode, the active pen is switched to a pressure detection mode, and in the pressure detection mode, the pressure sensing assembly detects a pressure signal according to the touched position and transmits the pressure signal to the control unit;

in the pressure detection mode, the control unit responds to the pen pressure signal and outputs a voltage signal after delaying for a period; and

in the pressure detection mode, the voltage signal is asynchronously transmitted to the touch chip through the transmitting part and the touch panel, and the voltage signal is used for detecting a pressure value.

8. The method as claimed in claim 7, wherein the pen driving signal is proportional to the pen sensing signal.

9. The sensing method of claim 7, wherein the period is adjusted according to a driving frequency of the panel driving signal.

10. The sensing method of claim 7, wherein after the touch signal is transmitted to the control unit, the control unit performs analog-to-digital conversion on the touch signal, and outputs the voltage signal according to the converted value.

11. The method as claimed in claim 7, wherein a time period for the control unit to output the voltage signal is proportional to a magnitude of the voltage signal.

12. The method as claimed in claim 7, wherein the frequency of the voltage signal is the same as the driving frequency of the panel driving signal.