TW201727460A - Capacitive touch device and detection method of capacitive touch panel thereof - Google Patents

Abstract

A capacitive touch device and a detection method of a capacitive touch panel thereof are provided. The capacitive touch device includes a plurality of touch electrodes, a detector unit, a plurality of switch units and a touch point determination unit. The detector unit is used for providing a plurality of capacitance after detecting the touch electrodes. The switch couples the detector unit to the touch electrodes and provides a ground voltage to the touch electrodes which are not coupled to the detector unit. The touch point determination unit couples to the detector unit to determine whether the touch electrodes are touched according the capacitance and provides a touch information accordingly.

Description

Capacitive touch device and method for detecting the same

The present invention relates to a touch device, and more particularly to a capacitive touch device and a method for detecting the same.

With the rapid development and application of information technology, wireless mobile communication and information appliances, in order to achieve portability, compactness and user-friendly operation, many electronic devices have been converted to use by traditional keyboard or mouse input devices. A touch panel is used as an input device. The current touch panel can be roughly divided into a capacitive touch panel and a resistive touch panel. The capacitive touch panel has a better sensing effect, and thus has become the mainstream of the current touch panel.

However, the capacitive touch panel detects the touch point through the change of the capacitance value of the touch electrode. The electrical properties of the capacitive touch panel are affected by the process and the stack structure. When the equivalent capacitance value of the capacitive touch panel changes too low, the touch point may not be detected correctly. Therefore, how to correctly detect the touch point when the equivalent capacitance value of the capacitive touch panel changes too low is a major focus of the development of the touch panel.

The invention provides a capacitive touch device and a method for detecting the capacitive touch panel thereof, which can improve the change of the capacitance value of the touch electrode when the finger or the stylus is touched.

The capacitive touch device of the present invention includes a plurality of touch electrodes, a detecting unit, a plurality of switching units, and a touch point determining unit. The detecting unit is configured to detect a plurality of capacitance values after detecting the touch electrodes. The switching units are coupled to the detecting unit and the touch electrodes, and receive a ground voltage. The switching unit couples the detecting unit to the touch electrodes and supplies the ground voltage to the touch electrodes of the uncoupled detecting unit. The touch point determining unit is coupled to the detecting unit to determine whether the touch electrodes are touched according to the capacitance values, and correspondingly provide a touch information.

The method for detecting a capacitive touch panel of the present invention, wherein the capacitive touch panel is located in a capacitive touch device, and the detecting method comprises the following steps. A detecting unit is coupled to the plurality of touch electrodes through the plurality of switching units, and a ground voltage is supplied to the touch electrodes of the uncoupled detecting unit through the switching units. A plurality of capacitance values are provided after detecting the touch electrodes through the detecting unit. A touch point determining unit determines whether the touch electrodes are touched according to the capacitance values, and provides a touch information according to whether the touch electrodes are touched or not.

Based on the above, the capacitive touch device and the method for detecting the capacitive touch panel of the embodiment of the present invention couple the touch electrodes of the uncoupled detection unit to a ground voltage, so that the touch finger or The stylus forms an equivalent capacitance with the grounded touch electrode. Thereby, the amount of change in the capacitance value of the touch electrode when the finger or the stylus is touched can be increased.

The above described features and advantages of the invention will be apparent from the following description.

FIG. 1 is a schematic diagram of a system of a capacitive touch device according to an embodiment of the invention. Referring to FIG. 1 , in the embodiment, the capacitive touch device 100 includes, for example, an electrical touch panel 110 , a plurality of switching units 120_1~120_x, a detecting unit 130, and a touch point determining unit 140, wherein the electrical touch The control panel 110 has a plurality of touch electrodes TE arranged in an array, and each of the touch electrodes TE corresponds to one switching unit (eg, 120_1~120_x), that is, x is a positive integer and is equal to the number of touch electrodes TE.

Each of the switching units (eg, 120_1~120_x) is coupled to one of the detecting unit 130 and the touch electrode TE, and receives the ground voltage GND. When the electrical touch panel 110 scans, at least one switching unit (such as 120_1~120_x) couples the detecting unit 130 with the corresponding touch electrode TE, and the remaining switching units (such as 120_1~120_x) will ground the voltage. GND is provided to the corresponding touch electrode TE, that is, the touch electrode TE of the uncoupled detection unit 130 is coupled to the ground voltage GND; when the electrical touch panel 110 is not scanned (ie, is idle) The switching units 120_1~120_x can provide the ground voltage GND to all of the touch electrodes TE or all the touch electrodes TE to be in a floating state, which may be determined by those skilled in the art.

After the detecting unit 130 is coupled to the touch electrode TE, the coupled touch electrode TE is detected, and after the detection is completed, a plurality of bit logic values VLC are provided to represent the touch electrode TE. The current equivalent capacitance value, that is, each touch electrode TE corresponds to a logic value VLC. The touch point determination unit 140 is coupled to the detection unit 130 to receive the logic value VLC corresponding to all the touch electrodes TE, and when the touch point determination unit 140 receives the logic value VLC corresponding to all the touch electrodes TE, The capacitance value represented by the logic value VLC determines whether the touch electrode TE is touched, and correspondingly provides the touch information Itou.

2A and 2B are schematic diagrams showing equivalent capacitances of a touch electrode when it is not touched according to an embodiment of the invention. 3A and 3B are schematic diagrams showing equivalent capacitances of a touch electrode when it is touched according to an embodiment of the invention. Referring to FIG. 1 , FIG. 2A , FIG. 2B , FIG. 3A and FIG. 3B , in the embodiment, the detecting unit 130 includes, for example, an analog-to-digital converter, and the switching units 120_1 120 120_x sequentially compare the analog-to-digital converters. The touch electrode TE is coupled. Then, after the analog digital converter detects one of the touch electrodes, the corresponding logic value VLC is provided to the touch point determining unit 140.

Referring to FIG. 2A, FIG. 2B, FIG. 3A and FIG. 3B, five touch electrodes TE1 to TE5 are described here. When the finger FG (or stylus) is not touched to the touch electrode TE of the detecting unit 130 (here, the touch electrode TE3 is taken as an example), there is an equivalent between the touch electrode TE3 and the ground voltage GND. The capacitor Cge does not form another equivalent capacitor, that is, the detecting unit 130 only detects the capacitance value of the equivalent capacitor Cge; when the finger (or stylus) touches the touch coupled to the detecting unit 130 In the electrode TE3, in addition to the equivalent capacitance Cge, the equivalent capacitance Cfe1~Cfe5 is formed between the touch electrodes TE1~TE5 and the finger FG, and an equivalent capacitance Cfg is also formed between the finger FG and the ground power GND. That is, the capacitance value detected by the detecting unit 130 is Cge+(Cfe3//(Cfg+Cfe1+Cfe2+Cfe4+Cfe5)), wherein the capacitance value of the touch electrode TE3 is Cfe3//(Cfg+Cfe1) +Cfe2 +Cfe4+Cfe5).

4A and FIG. 4B are schematic diagrams showing equivalent capacitances of the touch electrodes simultaneously detected when the touch electrodes are touched. Referring to FIG. 4A and FIG. 4B , in this embodiment, it is assumed that all the touch electrodes TE are simultaneously detected, that is, no touch electrodes TE are grounded. At this time, the touch electrodes TE are electrically independent. Therefore, when the touch electrode TE is touched by the finger FG (or the stylus), an equivalent capacitance Cfe is formed between the touch electrode TE and the finger FG, and the finger An equivalent capacitance Cfg is formed between the FG and the grounding power GND, that is, the capacitance value detected by the detecting unit 130 is Cge+Cfe//Cfg, and the capacitance value of the touch electrode TE is Cfe//Cfg. Among them, the capacitance value Cfe will be approximately equal to the capacitance value Cfe3.

Referring to FIG. 3A, FIG. 3B, FIG. 4A and FIG. 4B, since Cfg+Cfe1+Cfe2+Cfe4+Cfe5 will be larger than Cfg, Cfe3//(Cfg+Cfe1+Cfe2+Cfe4+Cfe5) will be larger than Cfe//Cfg. That is, the amount of change in the capacitance value detected by the grounding of the remaining touch electrodes is higher than the amount of change in the capacitance value detected by not grounding the remaining touch electrodes. Thereby, the touch sensitivity of the touch device and the recognition degree of the touch point can be enhanced.

In the above embodiment, the detecting unit 130 includes an analog digital converter, for example, but in other embodiments, the detecting unit 130 may include multiple analog digital converters to simultaneously detect multiple touch electrodes TE. The corresponding logic value VLC, but the undetected touch electrode TE is coupled to the ground voltage GND. Thereby, the number of analog digital converters can be reduced to reduce the hardware cost of the capacitive touch device.

FIG. 5 is a schematic diagram of grouping of capacitive touch panels according to an embodiment of the invention. Referring to FIG. 1 and FIG. 5, in the embodiment, the touch electrodes TE on the capacitive touch panel are respectively grouped (eg, GP1~GP4), and the touches of each group (such as GP1~GP4) are touched. The electrode TE can be detected independently. The detection method can be referred to the embodiment of FIG. 1 , FIG. 2A , FIG. 2B , FIG. 3A and FIG. 3B . In other words, each group (eg, GP1 GP GP 4 ) corresponds to n analog digits. Converter, where n is a positive integer. When each group (such as GP1~GP4) corresponds to an analog digital converter, each group (such as GP1~GP4) will detect one touch electrode TE at a time; when each group (such as GP1~GP4) is Corresponding to two analog-to-digital converters, each group (such as GP1~GP4) will detect two touch electrodes TE at a time, and the rest will be deduced by analogy.

In addition, the scanning of each group (such as GP1~GP4) can be synchronized, that is, the detection directions of the touch electrodes TE of each group (such as GP1~GP4) can be exactly the same, that is, each group (such as GP1~) The detection direction of the touch electrode TE of the GP4) can be synchronously scanned from the Z-shape or the N-type to the lower right corner from the upper left corner of the figure. On the other hand, the scanning of each group (such as GP1~GP4) may be out of synchronization, that is, the detection directions of the touch electrodes TE of each group (such as GP1~GP4) may not be exactly the same, that is, each group (such as GP1). The detection direction and the starting position of the touch electrode TE of the ~GP4) can be freely set, and the embodiment of the present invention is not limited thereto. When the scanning of each group (such as GP1~GP4) changes synchronously, the equivalent capacitance structure of the detected touch electrodes TE will be substantially the same to homogenize the capacitance distribution of the capacitive touch panel (such as 110).

FIG. 6 is a circuit diagram of a switching unit according to an embodiment of the invention. Referring to FIG. 1 and FIG. 6 , in the embodiment, each switching unit 120 a includes, for example, a first switch SW1 and a second switch SW2 . The first switch SW1 receives the switch signal SC1 and is coupled between the corresponding touch electrode TE and the analog digital converter ADC1 of the detecting unit 130a. The second switch SW2 receives the switch signal SC2 and is coupled between the corresponding touch electrode TE and the ground voltage GND. Wherein, at least one of the first switch SW1 and the second switch SW2 is off, and the switch signals SC1 and SC2 may be provided by the touch point judging unit 140 or by an additional control circuit, which may be determined by those skilled in the art.

FIG. 7 is a flow chart of a method for detecting a capacitive touch panel according to an embodiment of the invention. Referring to FIG. 7, in the embodiment, the capacitive touch panel is located in a capacitive touch device, and the detecting method includes the following steps. First, a detecting unit is coupled to the plurality of touch electrodes through the plurality of switching units, and a ground voltage is supplied to the touch electrodes of the uncoupled detecting unit through the switching units (step S710). Then, after detecting the touch electrodes through the detecting unit, a plurality of capacitance values are provided (step S710). Finally, a touch point determining unit is used to determine whether the touch electrodes are touched according to the capacitance values, and a touch information is correspondingly provided according to whether the touch electrodes are touched. The order of the steps S710, S720, and S730 is for illustrative purposes, and the embodiment of the present invention is not limited thereto. For details of the steps S710, S720, and S730, reference may be made to the embodiments of FIG. 1, FIG. 2A, FIG. 2B, FIG. 3A and FIG. 3B, FIG. 5 and FIG. 6, and details are not described herein again.

In summary, the capacitive touch device and the method for detecting the capacitive touch panel of the embodiment of the present invention couple the touch electrodes of the uncoupled detection unit to a ground voltage for touch control. The finger or stylus forms an equivalent capacitance with the grounded touch electrode. In this way, the amount of change in the capacitance of the touch electrode when the finger or the stylus is touched can be increased, thereby enhancing the touch sensitivity of the touch device and the recognition degree of the touch point.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

100‧‧‧Capacitive touch device
110‧‧‧Electric touch panel
120_1~120_x, 120a‧‧‧Switch unit
130, 130a‧‧‧Detection unit
140‧‧‧Touch point judgment unit
ADC1‧‧‧ Analog Digital Converter
Cge, Cfe, Cfe1~Cfe5‧‧‧ equivalent capacitance
FG‧‧ fingers
GND‧‧‧ Grounding voltage
GP1~GP4‧‧‧Group
Itou‧‧‧Touch Information
SC1, SC2‧‧‧ switching signals
SW1‧‧‧ first switch
SW2‧‧‧second switch
TE, TE1~TE5‧‧‧ touch electrodes
VLC‧‧‧ logical value
S710, S720, S730‧‧ steps

FIG. 1 is a schematic diagram of a system of a capacitive touch device according to an embodiment of the invention. 2A and 2B are schematic diagrams showing equivalent capacitances of a touch electrode when it is not touched according to an embodiment of the invention. 3A and 3B are schematic diagrams showing equivalent capacitances of a touch electrode when it is touched according to an embodiment of the invention. 4A and FIG. 4B are schematic diagrams showing equivalent capacitances of the remaining touch electrodes not coupled to the ground voltage when the touch electrodes are touched. FIG. 5 is a schematic diagram of grouping of capacitive touch panels according to an embodiment of the invention. FIG. 6 is a circuit diagram of a switching unit according to an embodiment of the invention. FIG. 7 is a flow chart of a method for detecting a capacitive touch panel according to an embodiment of the invention.

100‧‧‧Capacitive touch device

110‧‧‧Electric touch panel

120_1~120_x‧‧‧Switch unit

130‧‧‧Detection unit

140‧‧‧Touch point judgment unit

GND‧‧‧ Grounding voltage

Itou‧‧‧Touch Information

TE‧‧‧ touch electrode

VLC‧‧‧ logical value

Claims (15)

A capacitive touch device includes: a plurality of touch electrodes; a detecting unit for detecting a plurality of capacitance values after detecting the touch electrodes; and a plurality of switching units coupled to the detecting unit and the Touching the electrode and receiving a ground voltage, wherein the switching unit couples the detecting unit to the touch electrodes, and supplies the ground voltage to the touch electrodes that are not coupled to the detecting unit; And a touch point determining unit coupled to the detecting unit to determine whether the touch electrodes are touched according to the capacitance values, and correspondingly provide a touch information. The capacitive touch device of claim 1, wherein the touch electrodes are arranged in an array. The capacitive touch device of claim 1, wherein the detecting unit comprises an analog-to-digital converter, and the switching unit sequentially couples the analog-to-digital converter to the touch electrodes, and The analog-to-digital converter detects one of the touch electrodes and provides a corresponding capacitance value. The capacitive touch device of claim 1, wherein the detecting unit comprises a plurality of analog digital converters for respectively detecting corresponding touch electrodes to provide corresponding capacitance values. The capacitive touch device of claim 4, wherein the touch electrodes are divided into a plurality of groups, and each of the groups corresponds to n analog digital converters, wherein n is a positive integer. The capacitive touch device of claim 5, wherein the detection directions of the touch electrodes of each of the groups are identical. The capacitive touch device of claim 5, wherein the detection directions of the touch electrodes of each of the groups are not identical. The capacitive touch device of claim 1, wherein each of the switching units comprises: a first switch coupled between the corresponding touch electrode and the detecting unit; and a second switch And being coupled between the corresponding touch electrode and the ground voltage; wherein at least one of the first switch and the second switch is off. A method for detecting a capacitive touch panel, wherein the capacitive touch panel is located in a capacitive touch device, the detecting method includes: coupling a detecting unit to the plurality of touch electrodes through the plurality of switching units, and Providing a ground voltage to the touch electrodes that are not coupled to the detecting unit through the switching units; detecting the touch electrodes through the detecting unit to provide a plurality of capacitance values; and transmitting a touch point The determining unit determines whether the touch electrodes are touched according to the capacitance values, and provides a touch information according to whether the touch electrodes are touched. The method for detecting a capacitive touch panel according to claim 9, wherein the touch electrodes are arranged in an array. The method for detecting a capacitive touch panel according to claim 9 , wherein the detecting unit comprises an analog-to-digital converter, and detecting the touch electrodes through the detecting unit to provide a plurality of capacitance values The step of: connecting the analog digital converter to the touch electrodes in sequence through the switching units; and detecting the one of the touch electrodes through the analog digital converter to provide a corresponding capacitance value . The method for detecting a capacitive touch panel according to claim 9 , wherein the detecting unit comprises a plurality of analog digital converters, and the detecting unit detects the touch electrodes to provide a plurality of capacitors The value of the step includes: respectively, detecting corresponding touch electrodes through the analog digital converters to provide corresponding capacitance values. The method for detecting a capacitive touch panel according to claim 12, wherein the touch electrodes are divided into a plurality of groups, and each of the groups corresponds to n analog digital converters, wherein n is one A positive integer. The method for detecting a capacitive touch panel according to claim 13 is characterized in that the detection directions of the touch electrodes of each of the groups are completely the same. The method for detecting a capacitive touch panel according to claim 13 is characterized in that the detection directions of the touch electrodes of the groups are not completely the same.