CN109426380B

CN109426380B - Touch device, sensing method thereof and touch sensing circuit

Info

Publication number: CN109426380B
Application number: CN201710748229.7A
Authority: CN
Inventors: 王伟松; 张耀光
Original assignee: Himax Technologies Ltd
Current assignee: Himax Technologies Ltd
Priority date: 2017-08-28
Filing date: 2017-08-28
Publication date: 2021-12-21
Anticipated expiration: 2037-08-28
Also published as: CN109426380A

Abstract

A touch device, a sensing method thereof and a touch sensing circuit are provided. The touch device comprises a touch panel and a touch sensing circuit. In the first period, the touch sensing circuit simultaneously applies the same driving signal to a plurality of sensing electrodes of the touch panel, and performs self-capacitance touch detection on the sensing electrodes to obtain a self-capacitance detection result. In the second period, the touch sensing circuit performs mutual capacitance touch detection on at least one of the sensing electrodes to obtain a mutual capacitance detection result. The touch sensing circuit judges whether a touch event of the touch panel is caused by water according to the mutual capacitance detection result and the self-capacitance detection result.

Description

Touch device, sensing method thereof and touch sensing circuit

Technical Field

The present invention relates to touch sensing, and more particularly to a touch device, a touch sensing method thereof and a touch sensing circuit.

Background

In an in-cell (in-cell) touch sensing application, a common electrode layer (VCOM layer) of a display panel is used as a touch sensing electrode. The common electrode layer is cut into a plurality of blocks (a plurality of sensing electrodes) so as to locate the position of the touch event. The common electrode layer needs to be coupled to a common voltage during the display driving to ensure that the pixel liquid crystal can operate at the correct voltage. During touch sensing, the common electrode layer is coupled to a touch sensing circuit for touch sensing. In any case, the display panel may include data lines (or source lines) and scan lines (or gate lines) in addition to the common electrode layer. Therefore, a parasitic capacitance is formed between the common electrode layer and the data line, and a parasitic capacitance is also formed between the common electrode layer and the scan line. When the common electrode layer performs touch sensing, the parasitic capacitances affect the capacitance of the common electrode layer (sensing electrode). In order to reduce the influence of these parasitic capacitances on touch sensing, during touch sensing, in addition to a driving signal applied to the target sensing electrode (target common electrode), the same driving signal is applied to the data lines and the scan lines simultaneously, so as to eliminate the parasitic capacitances between the VCOM and the data lines and between the VCOM and the scan lines.

To prevent the touch error, when the touch sensing circuit detects a large-area touch event, the conventional touch sensing circuit usually ignores the large-area touch event, i.e. the touch sensing circuit does not report the position of the large-area touch event to the processor. In an actual touch situation, a wet finger is often used to perform a touch operation on the in-cell touch display panel. If the amount of water is a little more, the water brought by the wet finger occupies a large area on the in-cell touch display panel. The conventional touch sensing circuit cannot distinguish a large-area touch event caused by mistaken touch from a large-area touch event caused by a wet finger. The large-area touch event caused by the wet finger is usually a meaningful operation behavior of the user, however, the conventional touch sensing circuit usually considers the touch event caused by the wet finger as a false touch and ignores the touch event caused by the wet finger.

Disclosure of Invention

The invention provides a touch device, a sensing method of the touch device and a touch sensing circuit of the touch device, which can judge whether a touch event is caused by water.

The embodiment of the invention provides a touch device. The touch device comprises a touch panel and a touch sensing circuit. The touch panel has a plurality of sensing electrodes for sensing a touch event. The touch sensing circuit is coupled to the touch panel to read sensing information of the sensing electrodes. In the first period, the touch sensing circuit simultaneously applies the same driving signal to the sensing electrodes, and the touch sensing circuit performs self-capacitance touch detection (self-capacitance touch detection) on the sensing electrodes to obtain a self-capacitance detection result. In the second period, the touch sensing circuit performs mutual-capacitance touch detection (mutual-capacitance detection) on at least one of the sensing electrodes to obtain a mutual-capacitance detection result. The touch sensing circuit judges whether the touch event is caused by water according to the mutual capacitance detection result and the self-capacitance detection result. Wherein when the mutual capacitance detection result indicates that the touch event occurs on the touch panel, but the self-capacitance detection result indicates that the touch event does not occur on the touch panel, the touch sensing circuit determines that the touch event is caused by the water. When the touch sensing circuit determines that the touch event is caused by the water, the touch sensing circuit simultaneously applies the same driving signal to the sensing electrodes during a period when a user touches the water, and performs the self-contained touch detection on the sensing electrodes to obtain a position of the water, and reports the position of the water to a processor.

The embodiment of the invention provides a sensing method of a touch device. The sensing method comprises the following steps: providing a touch panel to sense a touch event; in a first period, a touch sensing circuit simultaneously applies the same driving signal to a plurality of sensing electrodes of a touch panel, and performs self-capacitance touch detection on the sensing electrodes to obtain a self-capacitance detection result; in a second period, the touch sensing circuit performs mutual capacitance touch detection on at least one sensing electrode in the sensing electrodes to obtain a mutual capacitance detection result; and judging whether the touch event is caused by water or not by the touch sensing circuit according to the mutual capacitance detection result and the self-capacitance detection result. Wherein when the mutual capacitance detection result indicates that the touch event occurs on the touch panel, but the self-capacitance detection result indicates that the touch event does not occur on the touch panel, the touch sensing circuit determines that the touch event is caused by the water. When the touch sensing circuit determines that the touch event is caused by the water, the touch sensing circuit simultaneously applies the same driving signal to the sensing electrodes during a period when a user touches the water, and performs the self-contained touch detection on the sensing electrodes to obtain a position of the water, and reports the position of the water to a processor.

The embodiment of the invention provides a touch sensing circuit, which is used for reading sensing information of a plurality of sensing electrodes of a touch panel. In the first period, the touch sensing circuit simultaneously applies the same driving signal to the sensing electrodes, and performs self-capacitance touch detection on the sensing electrodes to obtain a self-capacitance detection result. In the second period, the touch sensing circuit performs mutual capacitance touch detection on at least one of the sensing electrodes to obtain a mutual capacitance detection result. The touch sensing circuit judges whether a touch event of the touch panel is caused by water according to the mutual capacitance detection result and the self-capacitance detection result. Wherein when the mutual capacitance detection result indicates that the touch event occurs on the touch panel, but the self-capacitance detection result indicates that the touch event does not occur on the touch panel, the touch sensing circuit determines that the touch event is caused by the water. When the touch sensing circuit determines that the touch event is caused by the water, the touch sensing circuit simultaneously applies the same driving signal to the sensing electrodes during a period when a user touches the water, and performs the self-contained touch detection on the sensing electrodes to obtain a position of the water, and reports the position of the water to a processor.

Based on the above, the touch device, the sensing method of the touch device, and the touch sensing circuit of the touch device according to the embodiments of the invention can perform self-capacitance touch detection and mutual capacitance touch detection on the sensing electrodes. According to the mutual capacitance detection result and the self-capacitance detection result, the touch sensing circuit can judge whether the touch event is caused by water. Therefore, the touch event caused by the wet finger cannot be mistaken to be a large-area touch event caused by false touch.

In order to make the aforementioned and other features and advantages of the invention more comprehensible, embodiments accompanied with figures are described in detail below.

Drawings

Fig. 1 is a schematic diagram of a circuit block of a touch device according to an embodiment of the invention;

FIG. 2 is a schematic diagram illustrating a touch event of the touch panel shown in FIG. 1 according to an embodiment of the present invention;

FIG. 3 is a schematic diagram illustrating another scenario of a touch event of the touch panel shown in FIG. 1 according to an embodiment of the present invention;

FIG. 4 is a flowchart illustrating a sensing method of a touch device according to an embodiment of the invention;

FIG. 5 is a schematic diagram illustrating a situation where the touch panel shown in FIG. 1 performs self-contained touch detection according to an embodiment of the present invention;

FIG. 6 is a schematic diagram illustrating a situation in which the touch panel shown in FIG. 1 performs mutual capacitance touch detection according to an embodiment of the invention;

FIG. 7 is another exemplary diagram illustrating a self-contained touch detection performed by the touch panel shown in FIG. 1 according to an embodiment of the present invention; and

fig. 8 is a circuit block diagram illustrating the touch sensing circuit shown in fig. 1 according to an embodiment of the invention.

Detailed Description

The term "coupled (or connected)" as used throughout this specification, including the claims, may refer to any direct or indirect connection means. For example, if a first device couples (or connects) to a second device, it should be construed that the first device may be directly connected to the second device or the first device may be indirectly connected to the second device through some other device or some connection means. Further, wherever possible, the same reference numbers will be used throughout the drawings and the description to refer to the same or like parts. Elements/components/steps in different embodiments using the same reference numerals or using the same terms may be referred to one another in relation to the description.

Fig. 1 is a schematic circuit block diagram of a touch device 100 according to an embodiment of the invention. According to design requirements, the touch device 100 may be a mobile phone, a tablet computer, a notebook computer or other portable electronic devices. In other embodiments, the touch device 100 can be an advertisement device, a vending machine, a bus information inquiry machine, or other fixed electronic devices. The touch device 100 includes a touch panel 110, a touch sensing circuit 120, and a processor 130. The touch panel 110 has a plurality of sensing electrodes (e.g., the sensing electrode 111 shown in fig. 1). The touch panel 110 may sense a touch event. The touch panel 110 may be any type of capacitive touch panel according to design requirements. For example, in some embodiments, the touch panel 110 may be an in-cell (in-cell) touch display panel, and the sensing electrodes (e.g., the sensing electrodes 111 shown in fig. 1) in the touch panel 110 may be a plurality of common electrodes in the in-cell touch display panel. The common electrode is also referred to as a VCOM electrode.

The touch sensing circuit 120 is coupled to the touch panel 110 to read sensing information of the sensing electrodes in the touch panel 110. The touch sensing circuit 120 includes an Analog Front End (AFE) circuit, an analog-to-digital conversion circuit, a digital operation circuit, and/or other circuits/elements according to design requirements. The analog front-end circuit may be an existing analog front-end circuit or other read circuit/component. The analog-to-digital conversion circuit may be an existing analog-to-digital converter or other conversion circuit/component. The digital arithmetic circuit may be a microcontroller, microprocessor, or other processing circuit/element.

The processor 130 is coupled to the touch sensing circuit 120 to receive a processing result (i.e., position information of the touch event) of the touch sensing circuit 120. In some embodiments, the processor 130 may be a Central Processing Unit (CPU) to run an Operating System (OS). In other embodiments, the processor 130 may be a microcontroller, a microprocessor, an Application-specific integrated circuit (ASIC), a Digital Signal Processor (DSP), a Field Programmable Gate Array (FPGA), and/or other processing circuits/elements.

FIG. 2 is a schematic diagram illustrating a situation of a touch event of the touch panel 110 shown in FIG. 1 according to an embodiment of the present invention. The touch sensing circuit 120 may simultaneously apply the same driving signal to the sensing electrodes (e.g., the sensing electrode 111) in the touch panel 110, and the touch sensing circuit 120 may perform self-capacitance touch detection (self-capacitance touch detection) on the sensing electrodes. Therefore, when a large-area object 20 (e.g., a palm) touches the touch panel 110, the touch sensing circuit 120 can sense the large-area object 20 through one or more sensing electrodes overlapped on the large-area object 20. Since the contact area of the large-area object 20 on the touch panel 110 is larger than the threshold, the touch sensing circuit 120 can ignore the touch event caused by the large-area object 20, i.e. the touch sensing circuit 120 does not report the position of the large-area object 20 to the processor 130. Therefore, the touch sensing circuit 120 can prevent a false touch.

FIG. 3 is a schematic diagram illustrating another scenario of a touch event of the touch panel 110 shown in FIG. 1 according to an embodiment of the present invention. In an actual touch situation, the wet finger 30 is often used to touch the touch panel 110. If the amount of the water 31 is a little more, the water 31 brought by the wet finger 30 occupies a large area on the touch panel 110, as shown in fig. 3. If the touch sensing circuit 120 cannot distinguish whether the object on the touch panel 110 is water 31, the touch sensing circuit 120 may regard the touch event caused by the wet finger 30 as a false touch and ignore the touch event. However, the large area touch event caused by the wet finger 30 is usually a meaningful operation behavior of the user, rather than a false touch. Therefore, the touch sensing circuit 120 can perform the following sensing method to determine whether the touch event is caused by the water 31. When the touch sensing circuit 120 can recognize that the touch event is caused by the water 31, the touch sensing circuit 120 can report the position of the water 31 (i.e. the position of the wet finger 30) to the processor 130.

Fig. 4 is a flowchart illustrating a sensing method of the touch device 100 according to an embodiment of the invention. The sensing method shown in fig. 4 includes steps S410, S420, S430 and S440. It should be noted that the sequence of steps S410-S440 shown in fig. 4 is an exemplary embodiment, not the only way. For example, in other embodiments, the order of the steps S420 and S430 shown in fig. 4 may be reversed, that is, the step S430 may be performed first before the step S420 is performed.

Please refer to fig. 1 and fig. 4. Step S410 provides the touch panel 110 to sense a touch event. In the first period (step S420), the touch sensing circuit 120 may apply a same driving signal to the sensing electrodes (e.g., the sensing electrode 111) in the touch panel 110 at the same time, and perform self-capacitance touch detection on the sensing electrodes to obtain a self-capacitance detection result.

Fig. 5 is a schematic diagram illustrating a situation in which the touch panel 110 shown in fig. 1 performs self-contained touch detection according to an embodiment of the invention. Fig. 5 is a schematic cross-sectional view of the touch panel 110, and the touch panel 110 includes a sensing electrode 111_1, a sensing electrode 111_2, a sensing electrode 111_3, a sensing electrode 111_4, a sensing electrode 111_5, and a sensing electrode 111_ 6. The touch panel 110 has a cover layer 112 (e.g., a glass plate or other material) for a user to actually touch. When the water 31 covers the touch panel 110, as shown in fig. 5, a parasitic capacitance is formed between the water 31 and one or more sensing electrodes (e.g., the sensing electrodes 111_2 to 111_5 shown in fig. 5). In the self-capacitance touch detection, in addition to the target sensing electrode (e.g., the sensing electrode 111_4 shown in fig. 5) being applied with a driving signal, the non-target sensing electrode (the sensing electrode not being sensed currently) is also applied with the same driving signal to reduce the parasitic capacitance, as shown in fig. 5. According to design requirements, the self-contained touch detection can be the existing self-contained touch detection operation or other self-contained detection operations, and therefore the details are not repeated.

However, when performing self-capacitance touch detection, the parasitic capacitance is not equivalent because the signals at the two ends of the parasitic capacitance have the same waveform. According to the charge formula Q ═ C × V, when the voltage difference V between the two ends of the parasitic capacitor is 0, the charge amount Q ═ C × 0 of the parasitic capacitor is 0, that is, the capacitance value C of the parasitic capacitor is equivalent to 0. Therefore, in the situation shown in fig. 5, the touch sensing circuit 120 cannot determine that there is water 31 on the touch panel 110. That is, the self-contained detection result indicates that no touch event has occurred on the touch panel 110.

Please refer to fig. 1 and fig. 4. In the second period (step S430), the touch sensing circuit 120 may perform mutual capacitance touch detection on at least one target sensing electrode of the sensing electrodes of the touch panel 110 to obtain a mutual capacitance detection result. In the mutual capacitance touch detection, the target sensing electrode is coupled to the analog front end circuit of the touch sensing circuit 120, and the other sensing electrodes are applied with a driving signal.

Fig. 6 is a schematic diagram illustrating a situation in which the touch panel 110 shown in fig. 1 performs mutual capacitance touch detection according to an embodiment of the invention. The water 31, the touch panel 110, the sensing electrodes 111_1 to 111_6 and the covering layer 112 shown in FIG. 6 can refer to the related description of FIG. 5, and thus are not repeated. In the embodiment shown in fig. 6, the touch sensing circuit 120 includes an analog front-end circuit 121, an analog-to-digital converter 122, and other circuits/elements. An output of the analog front-end circuit 121 is coupled to an input of an analog-to-digital converter 122. In the second period (step S430), the touch sensing circuit 120 may perform mutual capacitance touch detection on at least one target sensing electrode (e.g., the sensing electrode 111_4) of the sensing electrodes of the touch panel 110 to obtain a mutual capacitance detection result. In the mutual capacitance touch detection, the target sensing electrode (e.g., the sensing electrode 111_4) is coupled to the analog front-end circuit 121 of the touch sensing circuit 120, and the other sensing electrodes (e.g., the sensing electrodes 111_1, 111_2, 111_3, 111_5, and 111_6) are applied with a driving signal. According to design requirements, the mutual capacitance type touch detection can be the existing mutual capacitance type touch detection operation or other mutual capacitance type detection operations, and therefore the details are not repeated. Therefore, the touch sensing circuit 120 can know that the object (water 31) is on the touch panel 110 in the second period (the period of the mutual capacitance touch detection).

In the embodiment shown in fig. 6, the analog front-end circuit 121 includes an operational amplifier 121_1 and a capacitor 121_ 2. The operational amplifier 121_1 has an inverting input terminal, a non-inverting input terminal, and an output terminal. The inverting input terminal of the operational amplifier 121_1 is coupled to the target sensing electrode (e.g., the sensing electrode 111_ 4). The first terminal and the second terminal of the capacitor 121_2 are coupled to the inverting input terminal and the output terminal of the operational amplifier 121_1, respectively. The output terminal of the operational amplifier 121_1 is coupled to the input terminal of the analog-to-digital converter 122. The non-inverting input terminal of the operational amplifier 121_1 is coupled to the reference voltage Vref. In a second period (the period of the mutual capacitance touch detection), the reference voltage Vref is a fixed voltage, and the analog front-end circuit 121 can perform the mutual capacitance touch detection on the target sensing electrode (e.g., the sensing electrode 111_ 4). In the first period (the period of self-contained touch detection), the reference voltage Vref is a frequency signal, and the analog front-end circuit 121 can perform self-contained touch detection on the target sensing electrode (e.g., the sensing electrode 111_ 4).

Please refer to fig. 1 and fig. 4. In step S440, the touch sensing circuit 120 can determine whether the touch event is caused by the water 31 according to the mutual capacitance detection result of step S430 and the self-capacitance detection result of step S420. For example, when the mutual capacitance detection result of step S430 indicates that the touch panel 110 has a touch event (see the description of fig. 6), but the self-capacitance detection result of step S420 indicates that the touch panel 110 has no touch event (see the description of fig. 5), the touch sensing circuit 120 may determine that the touch event is caused by the water 31.

Once it is known that the large-area touch event of the touch panel 110 is caused by the water 31, the touch sensing circuit 120 can report the location of the large-area touch event to the processor 130. For example, when the touch sensing circuit 120 determines in step S440 that the touch event is caused by the water 31, and during the period when the user touches the water 31, the touch sensing circuit 120 may simultaneously apply the same driving signal to the sensing electrodes, and perform the self-contained touch detection on the sensing electrodes again to obtain the position of the water 31, and report the position of the water 31 to the processor 130. When the touch sensing circuit 120 determines that the touch event is not caused by water, the touch sensing circuit 120 may ignore the large area touch event, i.e., not report the location of the large area touch event to the processor 130.

Fig. 7 is another schematic diagram illustrating another scenario of the touch panel 110 shown in fig. 1 performing self-contained touch detection according to an embodiment of the invention. The water 31, the touch panel 110, the sensing electrodes 111_1 to 111_6 and the covering layer 112 shown in FIG. 7 can refer to the related description of FIG. 5, and thus are not repeated. In the scenario shown in fig. 7, in addition to the water 31 contacting the touch panel 110, the wet finger 30 also contacts the touch panel 110. In the self-capacitance touch detection, in addition to the target sensing electrode (e.g., the sensing electrode 111_4 shown in fig. 7) being applied with a driving signal, the non-target sensing electrode (the sensing electrode not being sensed currently) is also applied with the same driving signal to reduce the parasitic capacitance, as shown in fig. 7. The self-contained touch detection shown in fig. 7 can refer to the related description of fig. 5, and thus is not repeated. The wet finger 30 may apply a reference voltage to the water 31. Therefore, in the situation shown in fig. 7, since the signals at the two ends of the parasitic capacitor have different waveforms, the touch sensing circuit 120 can sense the parasitic capacitor and further sense the position of the water 31. The touch sensing circuit 120 may then report the location of the water 31 back to the processor 130.

Fig. 8 is a circuit block diagram illustrating the touch sensing circuit 120 shown in fig. 1 according to an embodiment of the invention. In the embodiment shown in fig. 8, the touch sensing circuit 120 includes an analog front-end circuit 121, an analog-to-digital converter 122 and a switch circuit 123. The switch circuit 123 is coupled to an input of the analog front-end circuit 121. The switch circuit 123 is coupled to a plurality of same-row electrodes belonging to the same row in the sensing electrodes of the touch panel 110, as shown in fig. 8. During a first period (during self-contained touch detection), the switch circuit 123 simultaneously couples the column electrodes to the input end of the analog front-end circuit 121, so that the analog front-end circuit 121 performs self-contained touch detection on the column electrodes. In a second period (a period of mutual capacitance touch detection), the switch circuit 123 couples the column electrodes to the input end of the analog front-end circuit 121 in turn, so that the analog front-end circuit 121 performs mutual capacitance touch detection on the column electrodes in a time-sharing manner.

In the embodiment shown in fig. 8, the analog front-end circuit 121 includes an operational amplifier 121_1 and a capacitor 121_ 2. The operational amplifier 121_1 has an inverting input terminal, a non-inverting input terminal, and an output terminal. The inverting input terminal of the operational amplifier 121_1 is coupled to the switching circuit 123. The first terminal and the second terminal of the capacitor 121_2 are coupled to the inverting input terminal and the output terminal of the operational amplifier 121_1, respectively. The output terminal of the operational amplifier 121_1 is coupled to the input terminal of the analog-to-digital converter 122. The non-inverting input terminal of the operational amplifier 121_1 is coupled to the reference voltage Vref. In a second period (the period of the mutual capacitance touch detection), the reference voltage Vref is a fixed voltage, and the analog front-end circuit 121 can perform the mutual capacitance touch detection on the target sensing electrode (e.g., the sensing electrode 111_ 4). In the first period (the period of self-contained touch detection), the reference voltage Vref is a frequency signal, and the analog front-end circuit 121 can perform self-contained touch detection on the target sensing electrode (e.g., the sensing electrode 111_ 4).

By coupling the column electrodes to the input terminal of the analog front-end circuit 121 through the switch circuit 123, the touch sensing circuit 120 can obtain the mutual capacitance detection result of the touch panel 110 in a short time (e.g., one cycle). In the embodiment shown in fig. 8, although the touch sensing circuit 120 cannot know the precise location of the touch event during the mutual capacitance touch detection, the touch sensing circuit 120 can detect whether the touch panel 110 has the touch event in a short time (e.g., a cycle) by mutual capacitance detection, and further determine whether the touch event is a large-area touch event caused by water 31. Once it is determined that the large-area touch event is caused by the water 31, the touch sensing circuit 120 may perform a self-contained touch detection on the sensing electrodes again to obtain the position of the water 31 during the period when the user touches the water 31, and report the position of the water 31 to the processor 130. When the touch sensing circuit 120 determines that the large-area touch event of the touch panel 110 is not caused by water, the touch sensing circuit 120 ignores the large-area touch event, i.e., does not report the location of the large-area touch event to the processor 130.

It is noted that, in various application scenarios, the related functions of the touch sensing circuit 120 and/or the processor 130 may be implemented as software, firmware or hardware by using a general programming language (e.g., C or C + +), a hardware description language (e.g., Verilog HDL or VHDL), or other suitable programming languages. The programming language that can perform the related functions may be arranged as any known computer-accessible media such as magnetic tapes (magnetic tapes), semiconductor (semiconductors) memories, magnetic disks (magnetic disks) or optical disks (compact disks such as CD-ROM or DVD-ROM), or may be transmitted through the Internet (Internet), wired communication, wireless communication or other communication media. The programming language may be stored in an accessible medium of the calculator to facilitate access/execution of programming codes of the software (or firmware) by a processor of the calculator. For a hardware implementation, various logic blocks, modules, and circuits within one or more controllers, microcontrollers, microprocessors, Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Field Programmable Gate Arrays (FPGAs), and/or other processing units may be used to implement or perform the functions described in the embodiments herein. In addition, the apparatus and method of the present invention may be implemented by a combination of hardware and software.

In summary, the touch device 100, the sensing method of the touch device 100, and the touch sensing circuit 120 of the touch device 100 according to the embodiments of the invention can perform self-capacitive touch detection and mutual capacitive touch detection on the sensing electrodes of the touch panel 110. According to the mutual capacitance detection result and the self-capacitance detection result, the touch sensing circuit 120 can determine whether the touch event of the touch panel 110 is caused by water. Therefore, the large-area touch event caused by the wet finger 30 is not mistaken as a large-area touch event caused by a false touch.

Although the present invention has been described with reference to the above embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention.

Description of the symbols

20: large area object

30: wet finger

31: water (W)

100: touch control device

110: touch panel

111. 111_1, 111_2, 111_3, 111_4, 111_5, 111_ 6: sensing electrode

112: covering layer

120: touch sensing circuit

121: analog front-end circuit

121_ 1: operational amplifier

121_ 2: capacitor with a capacitor element

122: analog-to-digital converter

123: switching circuit

130: processor with a memory having a plurality of memory cells

S410, S420, S430, S440: step (ii) of

Vref: reference voltage

Claims

1. A touch device, comprising:

a touch panel having a plurality of sensing electrodes for sensing a touch event; and

a touch sensing circuit coupled to the touch panel for reading sensing information of the sensing electrodes, wherein

In a first period, the touch sensing circuit simultaneously applies the same driving signal to the sensing electrodes, and the touch sensing circuit performs self-capacitance touch detection on the sensing electrodes to obtain a self-capacitance detection result,

in a second period, the touch sensing circuit performs mutual capacitance touch detection on at least one of the sensing electrodes to obtain a mutual capacitance detection result, an

The touch sensing circuit judges whether the touch event is caused by water according to the mutual capacitance detection result and the self-capacitance detection result,

wherein the touch sensing circuit determines that the touch event is caused by the water when the mutual capacitance detection result indicates that the touch event occurs on the touch panel, but the self-capacitance detection result indicates that the touch event does not occur on the touch panel,

when the touch sensing circuit determines that the touch event is caused by the water, the touch sensing circuit simultaneously applies the same driving signal to the sensing electrodes during a period when a user touches the water, and performs the self-contained touch detection on the sensing electrodes to obtain a position of the water, and reports the position of the water to a processor.

2. The touch device of claim 1, wherein the touch panel is an in-cell touch display panel, and the plurality of sensing electrodes are a plurality of common electrodes in the in-cell touch display panel.

3. The touch device of claim 1, wherein the touch sensing circuit comprises:

an analog front end circuit; and

a switch circuit coupled to an input terminal of the analog front-end circuit and coupled to a plurality of same-column electrodes belonging to a same column among the plurality of sensing electrodes, wherein

During the first period, the switch circuit simultaneously couples the plurality of column electrodes to the input terminal of the analog front-end circuit, so that the analog front-end circuit performs the self-contained touch detection on the plurality of column electrodes, and

during the second period, the switch circuit couples the plurality of column electrodes to the input end of the analog front-end circuit in turn, so that the analog front-end circuit performs the mutual capacitance touch detection on the plurality of column electrodes in a time-sharing manner.

4. The touch device of claim 3, wherein the analog front end circuit comprises:

an operational amplifier having an inverting input terminal, a non-inverting input terminal and an output terminal, wherein the inverting input terminal is coupled to the switching circuit, and the non-inverting input terminal is coupled to a reference voltage; and

a capacitor having a first end and a second end, the first end and the second end being coupled to the inverting input terminal and the output terminal of the operational amplifier, respectively.

5. The touch device of claim 4, wherein the reference voltage is a clock signal during the first period and a fixed voltage during the second period.

6. A sensing method of a touch device comprises the following steps:

providing a touch panel to sense a touch event;

in a first period, a touch sensing circuit simultaneously applies the same driving signal to a plurality of sensing electrodes of the touch panel, and performs self-capacitance touch detection on the plurality of sensing electrodes to obtain a self-capacitance detection result;

in a second period, the touch sensing circuit performs mutual capacitance touch detection on at least one sensing electrode in the plurality of sensing electrodes to obtain a mutual capacitance detection result; and

determining, by the touch sensing circuit, whether the touch event is caused by water according to the mutual capacitance detection result and the self-capacitance detection result,

7. The sensing method of claim 6, wherein the touch panel is an in-cell touch display panel, and the sensing electrodes are common electrodes in the in-cell touch display panel.

8. A touch sensing circuit is used for reading sensing information of a plurality of sensing electrodes of a touch panel, wherein:

in a first period, the touch sensing circuit simultaneously applies the same driving signal to the sensing electrodes and performs self-capacitance touch detection on the sensing electrodes to obtain a self-capacitance detection result,

The touch sensing circuit judges whether a touch event of the touch panel is caused by water according to the mutual capacitance detection result and the self-capacitance detection result,

9. The touch sensing circuit of claim 8, comprising:

an analog front end circuit; and

10. The touch sensing circuit of claim 9, wherein the analog front end circuit comprises:

11. The touch sensing circuit of claim 10, wherein the reference voltage is a frequency signal during the first period, and the reference voltage is a fixed voltage during the second period.