WO2014127714A1

WO2014127714A1 - Method and apparatus for detecting touch on capacitive touch screen

Info

Publication number: WO2014127714A1
Application number: PCT/CN2014/072224
Authority: WO
Inventors: Zhengang Li; Chen Huang; Yun Yang
Original assignee: Shenzhen Byd Auto R&D Company Limited; Byd Company Limited
Priority date: 2013-02-19
Filing date: 2014-02-19
Publication date: 2014-08-28
Also published as: CN103995627B; CN103995627A

Abstract

A method and an apparatus for detecting a touch on a capacitive touch screen are provided. The method includes: detecting a self-capacitance and a mutual capacitance of the capacitive touch screen in real-time, in which the self-capacitance and the mutual capacitance are detected in a time-sharing mode; determining whether a current self-capacitance changes with respect to a previous self-capacitance and whether a current mutual capacitance changes with respect to a previous mutual capacitance; determining that the capacitive touch screen is touched by a finger when the current self-capacitance changes with respect to the previous self-capacitance and the current mutual capacitance changes with respect to the previous mutual capacitance; determining that the capacitive touch screen is not touched by the finger when the current self-capacitance does not change with respect to the previous self-capacitance.

Description

METHOD AND APPARATUS FOR DETECTING TOUCH ON CAPACITIVE TOUCH

SCREEN

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority and benefits of Chinese Patent Application No.

201310053607.1, filed with State Intellectual Property Office, P. R. C. on February 19, 2013, the entire content of which is incorporated herein by reference.

FIELD

Embodiments of the present disclosure generally relate to a touch screen field, and more particularly, to a method and an apparatus for detecting a touch on a capacitive touch screen.

BACKGROUND

Conventional methods for scanning a capacitive touch screen typically include a self-capacitance scanning method and a mutual capacitance scanning method. The self-capacitance scanning method refers to scanning a capacitance formed between a channel in the capacitive touch screen and a finger touching the screen, while the mutual capacitance scanning method refers to scanning a capacitance formed between channels in the capacitive touch screen. The self-capacitance scanning method is lightly influenced by water and has a great anti-interference capability, but cannot recognize a multi-touch, i.e., only supports a single touch. The mutual capacitance scanning method can support the multi-touch and is widely applied in smart phones and tablet computers. However, the mutual capacitance scanning method has a lower waterproof property and a lower anti-interference capability than the self-capacitance scanning method. During the mutual capacitance scanning, when there is water on the capacitive touch screen, the scanned capacitance increases; when there is a finger touch on the capacitive touch screen, the scanned capacitance decreases; when there are both water and the finger touch on the capacitive touch screen, the scanned capacitance is less than that obtained when there is only the finger touch on the capacitive touch screen. According to the above principles, whether there is water or the finger touch on the capacitive touch screen can be recognized by software, however, it is difficult to realize. Since whether there has been water on the capacitive touch screen before the capacitive touch screen is turned on cannot be determined, and if the scanned mutual capacitance decreases when the water is wiped away from the touch screen, the software may probably misjudge that the capacitive touch screen is touched constantly by the finger. Thus, interference points will appear in the capacitive touch screen continuously, even resulting in a dysfunction.

In addition, charger interference generally influences the mutual capacitance scanning. The frequency of the charger is generally close to the scanning frequency of the mutual capacitance scanning method. Once the frequency of the charger is too close to the scanning frequency of the mutual capacitance scanning method, it is easy to cause incorrect reporting in the touch screen. Thus, a frequency avoiding method is used to avoid the charger interference, i.e., the scanning frequency of the mutual capacitance scanning method is as far away from the charger frequency as possible. However, frequencies of chargers are different from each other and frequencies of different types of chargers also have a big difference from each other. Thus, the frequency of each type of charger is adjusted once during the production. However, with the above method, it cannot ensure that the charger interference can be avoided for all the products, and once another type of charger is used to replace the original charger, problems will come out.

In conclusion, conventional self-capacitance scanning method and mutual capacitance scanning method cannot determine a touch location accurately, and have a low anti-interference capability when there is the water interference or the charger interference. SUMMARY

Embodiments of the present disclosure seek to solve at least one of the problems existing in the prior art to at least some extent.

For this, a first objective of embodiments of the present disclosure is to provide a method for detecting a touch on a capacitive touch screen, which can accurately determine a location touched by a finger, reduce interferences and improve the production efficiency.

A second objective of embodiments of the present disclosure is to provide an apparatus for detecting a touch on a capacitive touch screen.

In order to realize the above objectives, according to embodiments of a first broad aspect of the present disclosure, there is provided a method for detecting a touch on a capacitive touch screen including: detecting a self-capacitance and a mutual capacitance of the capacitive touch screen in real-time, in which the self-capacitance and the mutual capacitance are detected in a time-sharing mode; determining whether a current self-capacitance changes with respect to a previous self-capacitance and whether a current mutual capacitance changes with respect to a previous mutual capacitance; determining that the capacitive touch screen is touched by a finger when the current self-capacitance changes with respect to the previous self-capacitance and the current mutual capacitance changes with respect to the previous mutual capacitance; and determining that the capacitive touch screen is not touched by the finger when the current self-capacitance does not change with respect to the previous self-capacitance, no matter whether the current mutual capacitance changes with respect to the previous mutual capacitance or not.

With the method for detecting a touch on a capacitive touch screen according to embodiments of the present disclosure, by detecting the self-capacitance and the mutual capacitance of the capacitive touch screen in a time- sharing mode, an anti-interference performance of the capacitive touch screen is improved greatly. Moreover, by determining whether the capacitive touch screen is touched by the finger according to the change between the detected self-capacitance and the previous self-capacitance and the change between the detected mutual capacitance and the previous mutual capacitance, the determination is more accurate. Furthermore, frequencies of chargers are not required to be adjusted during the production, thus improving the production efficiency and reducing the cost.

In some embodiments, detecting a self-capacitance of the capacitive touch screen includes: detecting a first sensing value of a row sensor when the row sensor is excited; and detecting a second sensing value of a column sensor when the column sensor is excited.

In some embodiments, detecting a mutual capacitance of the capacitive touch screen includes: detecting a third sensing value of each of a plurality of column sensors when a row sensor is excited; and detecting a fourth sensing value of each of a plurality of row sensors when a column sensor is excited.

In some embodiments, the method further includes determining a location touched by the finger.

In some embodiments, determining a location touched by the finger includes: determining a self-capacitance positioning result according to a result of detecting the self-capacitance; determining a mutual capacitance positioning result according to a result of detecting the mutual capacitance; and determining the location touched by the finger according to the self-capacitance positioning result and the mutual capacitance positioning result. In some embodiments, determining a self-capacitance positioning result according to a result of detecting the self-capacitance includes: determining a row corresponding to the row sensor having the first sensing value larger than the predetermined value as a self-capacitance positioning row; and determining a column corresponding to the column sensor having the second sensing value larger than the predetermined value as a self-capacitance positioning column.

In some embodiments, determining a mutual capacitance positioning result according to a result of detecting the mutual capacitance includes: determining an intersection point between a column corresponding to the column sensor having the third sensing value larger than the predetermined value and a row corresponding to a correspondingly excited row sensor as a mutual capacitance positioning point; or determining an intersection point between a row corresponding to the row sensor having the fourth sensing value larger than the predetermined value and a column corresponding to a correspondingly excited column sensor as a mutual capacitance positioning point.

In some embodiments, determining a mutual capacitance positioning result according to a result of detecting the mutual capacitance further includes: obtaining a mutual capacitance positioning coordinate according to the mutual capacitance positioning point.

In some embodiments, determining the location touched by the finger includes: determining whether a row of the mutual capacitance positioning coordinate is the same as the self-capacitance positioning row or whether a column of the mutual capacitance positioning coordinate is the same as the self-capacitance positioning column; and if yes, determining the mutual capacitance positioning point as the location touched by the finger.

In some embodiments, the method further includes determining whether there is an interference on the capacitive touch screen according to a change between the current mutual capacitance and the previous mutual capacitance when the current self-capacitance does not change with respect to the previous self-capacitance.

According to embodiments of a second broad aspect of the present disclosure, there is provided an apparatus for detecting a touch on a capacitive touch screen including: a first detecting module, configured to detect a self-capacitance of the capacitive touch screen in real-time; a second detecting module, configured to detect a mutual capacitance of the capacitive touch screen in real-time; a switching module, connected with the first detecting module and the second detecting module respectively; and a control module, connected with the switching module, and configured to generate a control signal for controlling the switching module to turn on or off the first detecting module and the second detecting module at different time, to determine that the capacitive touch screen is touched by a finger when a current self-capacitance changes with respect to a previous self-capacitance and a current mutual capacitance changes with respect to a previous mutual capacitance, and to determine that the capacitive touch screen is not touched by the finger when the current self-capacitance does not change with respect to the previous self-capacitance.

In some embodiments, the apparatus further includes an exciting module, configured to excite a plurality of row sensors and a plurality of column sensors in the capacitive touch screen.

In some embodiments, the first detecting module includes: a first row detecting unit, configured to detect a first sensing value of the row sensor when the row sensor is excited; a first column detecting unit, configured to detect a second sensing value of the column sensor when the column sensor is excited.

In some embodiments, the second detecting module includes: a second row detecting unit, configured to detect a third sensing value of each of the plurality of row sensors when each of the plurality of column sensors is excited; and a second column detecting unit, configured to detect a fourth sensing value of each of the plurality of column sensors when each of the plurality of row sensors is excited.

In some embodiments, the control module is further configured to determine a location touched by the finger.

In some embodiments, the control module is configured to: determine a row corresponding to the row sensor having the first sensing value larger than the predetermined value as a self-capacitance positioning row; determine a column corresponding to the column sensor having the second sensing value larger than the predetermined value as a self-capacitance positioning column; determine an intersection point between a column corresponding to the column sensor having the third sensing value larger than the predetermined value and a row corresponding to a correspondingly excited row sensor as a mutual capacitance positioning point; or determine an intersection point between a row corresponding to the row sensor having the fourth sensing value larger than the predetermined value and a column corresponding to a correspondingly excited column sensor as a mutual capacitance positioning point; obtain a mutual capacitance positioning coordinate according to the mutual capacitance positioning point; and determine the mutual capacitance positioning point as the location touched by the finger when a row of the mutual capacitance positioning coordinate is the same as the self-capacitance positioning row or a column of the mutual capacitance positioning coordinate is the same as the self-capacitance positioning column.

In some embodiments, the apparatus further includes a communicating module, in which the control module communicates with a host computer via the communicating module, such that the control module sends interference information to the host computer according to a change between the current mutual capacitance and the previous mutual capacitance when the current self-capacitance does not change with respect to the previous self-capacitance.

With the apparatus for detecting a touch on a capacitive touch screen according to embodiments of the present disclosure, by making use of the first detecting module and the second detecting module to detect the self-capacitance and the mutual capacitance of the capacitive touch screen at different time, the control module can determine whether the capacitive touch screen is touched by the finger more accurately. Furthermore, with the apparatus for detecting a touch on a capacitive touch screen according to the present disclosure, it is possible to avoid the water interference and the charger interference, thus improving the positioning accuracy of the capacitive touch screen.

Additional aspects and advantages of embodiments of present disclosure will be given in part in the following descriptions, become apparent in part from the following descriptions, or be learned from the practice of the embodiments of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects and advantages of embodiments of the present disclosure will become apparent and more readily appreciated from the following descriptions made with reference to the accompanying drawings, in which:

Fig. 1 is a flow chart of a method for detecting a touch on a capacitive touch screen according to an embodiment of the present disclosure;

Fig. 2 is a flow chart of determining a location touched by a finger according to an embodiment of the present disclosure;

Fig. 3 is a schematic diagram of an apparatus for detecting a touch on a capacitive touch screen according to an embodiment of the present disclosure; Fig. 4 is a schematic diagram illustrating a connection between a capacitive touch screen and an apparatus for detecting a touch thereon according to an embodiment of the present disclosure;

Fig. 5 is a schematic diagram of an apparatus for detecting a touch on a capacitive touch screen according to another embodiment of the present disclosure.

DETAILED DESCRIPTION

Reference will be made in detail to embodiments of the present disclosure. The same or similar elements and the elements having same or similar functions are denoted by like reference numerals throughout the descriptions. The embodiments described herein with reference to drawings are explanatory, illustrative, and used to generally understand the present disclosure. The embodiments shall not be construed to limit the present disclosure.

The following disclosure provides a plurality of embodiments for implementing different structures of the present disclosure. In order to simply the present disclosure, the elements and dispositions in special embodiments will be described in the following. Surely, the elements and dispositions are explanatory, but not used to limit the present disclosure. In addition, repeated numbers and/or letters may be referred to in different embodiments of the present disclosure, which is for the purpose of simplification and clarity, and the repeated numbers and/or letters themselves do not indicate the relation between each of the described embodiments and/or dispositions. Moreover, embodiments of the present disclosure provide a plurality of processing and material, however those having the ordinary skills in the related art should recognize the applicability of other processing and materials. Further, in the description of the present disclosure, a structure in which a first feature is "on" a second feature may include an embodiment in which the first feature directly contacts the second feature, and may also include an embodiment in which an additional feature is formed between the first feature and the second feature so that the first feature does not directly contact the second feature, unless otherwise specified.

In the description of the present disclosure, unless specified or limited otherwise, it should be noted that, terms "mounted," "connected," "coupled," and "fastened" may be understood broadly, such as permanent connection or detachable connection, electronic connection or mechanical connection, direct connection or indirect connection via intermediary, inner communication or interaction between two elements. These having ordinary skills in the art should understand the specific meanings in the present disclosure according to specific situations. With reference to the following descriptions and drawings, these and other aspects of embodiments of the present disclosure will be transparent. In these descriptions and drawings, explanatory embodiments have been shown and described to illustrate some modes of implementing the theory in embodiments of the present disclosure, it would be appreciated by those skilled in the art that the above embodiments cannot be construed to limit the present disclosure, and changes, alternatives, and modifications can be made in the embodiments without departing from spirit, principles and scope of the present disclosure.

In the following, a method for detecting a touch on a capacitive touch screen will be described with reference to Figs. 1 and 2.

Fig. 1 is a flow chart of a method for detecting a touch on a capacitive touch screen according to an embodiment of the present disclosure. As shown in Fig. 1, the method includes the following steps.

At step 1, a self-capacitance and a mutual capacitance of the capacitive touch screen are detected in real-time, in which the self-capacitance and the mutual capacitance are detected in a time- sharing mode. In other words, the self-capacitance and the mutual capacitance are detected at different time, i.e., the self-capacitance is detected firstly and then the mutual capacitance is detected, or the mutual capacitance is detected firstly and then the self-capacitance is detected.

Specifically, there are a plurality of row sensors and a plurality of column sensors in the capacitive touch screen, and the plurality of row sensors and the plurality of column sensors are detected for detecting the self-capacitance and the mutual capacitance. More specifically, for detecting the self-capacitance, a first sensing value of a row sensor is detected when the row sensor is excited and a second sensing value of a column sensor is detected when the column sensor is excited. For detecting the mutual capacitance, a third sensing value of each of the plurality of column sensors is detected when a row sensor is excited, or a fourth sensing value of each of the plurality of row sensors is detected when a column sensor is excited.

At step 2, whether a current self-capacitance changes with respect to a previous self-capacitance and whether a current mutual capacitance changes with respect to a previous mutual capacitance are determined.

At step 3, it is determined that the capacitive touch screen is touched by a finger when the current self-capacitance changes with respect to the previous self-capacitance and the current mutual capacitance changes with respect to the previous mutual capacitance. At step 4, it is determined that the capacitive touch screen is not touched by the finger when the current self-capacitance does not change with respect to the previous self-capacitance.

Specifically, taking the situation that the self-capacitance is detected firstly and then the mutual capacitance is detected as an example, whether the capacitive touch screen is touched by the finger can be determined according to a result of detecting the self-capacitance. This is because the self-capacitance only changes when the capacitive touch screen is touched by the finger but does not change when there is water or other conductive objects on the screen. Then, if the mutual capacitance does not change, it can be determined that the capacitive touch screen is not touched by any object; if the mutual capacitance changes, it can be determined that there is water or other conductive objects (such as a coin) on the screen and a special protection process (such as a waterproofing process) can be performed.

In other words, no matter whether the self-capacitance is detected firstly or the mutual capacitance is detected firstly, it can be determined that the capacitive touch screen is not touched by the finger when the self-capacitance does not change, and whether there is an interference on the capacitive touch screen can be determined according to the result of detecting the mutual capacitance. For example, compared with the condition that there is not any touch or any interference on the capacitive touch screen, if the self-capacitance does not change but the mutual capacitance increases, it can be determined that there is water or other conductive objects (such as the coin) on the touch screen. Subsequently, if the self-capacitance does not change but the mutual capacitance decreases, it can be determined that the water is wiped off or the conductive objects are removed from the touch screen. If the self-capacitance does not change but a relatively large noisy data occasionally occurs to the mutual capacitance, it can be determined that a charger interferes with the touch screen.

In addition, when it is determined that there is an interference, a corresponding anti-interference algorithm can be adopted to protect the touch screen from interference. For example, if there is water or other conductive objects (such as the coin) on the touch screen, a waterproofing algorithm can be run to improve the waterproof capability of the touch screen. If there is an action of wiping the water away from the touch screen, the reference value of the mutual capacitance can be updated quickly to adapt to the interference. If the noise increases, a frequency-hopping scanning can be executed or the predetermined value can be enhanced to improve the noisy immunity capability. Then, reference values of the self-capacitance and the mutual capacitance are updated, and that cycle repeats. Thus, it is possible to protect the capacitive touch screen from external interference, thus avoiding misjudgment such as incorrect reporting, jumping reporting and non-reporting.

Furthermore, when it is determined that the capacitive touch screen is touched by the finger, a location touched by the finger can be determined. Fig. 2 is a flow chart of determining a location touched by a finger according to an embodiment of the present disclosure. As shown in Fig. 2, the method for determining the location touched by the finger includes the following steps.

At step 31, a self-capacitance positioning result is determined according to a result of detecting the self-capacitance.

Specifically, the first sensing value of each row sensor is compared with a predetermined value, and a row corresponding to the row sensor having the first sensing value larger than the predetermined value is determined as a self-capacitance positioning row. Likewise, the second sensing value of each column sensor is compared with the predetermined value, and a column corresponding to the column sensor having the second sensing value larger than the predetermined value is determined as a self-capacitance positioning column. The self-capacitance positioning result is constituted of the self-capacitance positioning row and the self-capacitance positioning column.

At step 32, a mutual capacitance positioning result is determined according to a result of detecting the mutual capacitance.

Specifically, the third sensing value of each column sensor is compared with the predetermined value, and an intersection point between a column corresponding to the column sensor having the third sensing value larger than the predetermined value and a row corresponding to a correspondingly excited row sensor is determined as a mutual capacitance positioning point. Alternatively, the fourth sensing value of each row sensor is detected, and an intersection point between a row corresponding to the row sensor having the fourth sensing value larger than the predetermined value and a column corresponding to a correspondingly excited column sensor is determined as a mutual capacitance positioning point. In one embodiment, the result of detecting the mutual capacitance is presented in a form of matrix, i.e., the obtained mutual capacitance positioning points are matrix data.

Table 1 is a table illustrating difference values between the matrix data and a reference value

(i.e., the sensing value of the sensor when the location corresponding to the sensor is not touched), in which X1-X20 represent the plurality of row sensors and Yl-Yll represent the plurality of column sensors.

Table 1. difference values

In one embodiment, when the difference value is larger than the predetermined value (for example, 500), the location corresponding to the difference value is determined as the location touched by the finger. As shown in Table 1, the difference value at the intersection point between the row corresponding to row sensor Xll and the column corresponding to column sensor Y7 is 1464 and the difference value at the intersection point between the row corresponding to row sensor X12 and the column corresponding to column sensor Y7 is 1120, so these two intersection points are points touched by the finger. With a matrix coordinate algorithm, a coordinate corresponding to each finger can be obtained, i.e., a mutual capacitance positioning coordinate is obtained. The matrix coordinate algorithm is a known technology by those skilled in the art and will be omitted herein.

At step 33, the location touched by the finger is determined according to the self-capacitance positioning result and the mutual capacitance positioning result.

Specifically, a row of the mutual capacitance positioning coordinate is compared with the self-capacitance positioning row or a column of the mutual capacitance positioning coordinate is compared with the self-capacitance positioning column. If the row of the mutual capacitance positioning coordinate is the same as the self-capacitance positioning row or the column of the mutual capacitance positioning coordinate is the same as the self-capacitance positioning column, the mutual capacitance positioning point is determined as the location touched by the finger.

It should be noted that, since there is an error during detection or calculation, when the row of the mutual capacitance positioning coordinate is substantially the same as the self-capacitance positioning row or the column of the mutual capacitance positioning coordinate is substantially the same as the self-capacitance positioning column, the mutual capacitance positioning point can be determined as the location touched by the finger.

In conclusion, with the method for detecting a touch on a capacitive touch screen according to embodiments of the present disclosure, by detecting the self-capacitance and the mutual capacitance of the capacitive touch screen in a time- sharing mode, an anti-interference performance of the capacitive touch screen can be improved greatly. Moreover, when it is determined that the capacitive touch screen is touched by the finger, the touch location can be determined accurately according to the positioning results of detecting the self-capacitance and the mutual capacitance. Furthermore, frequencies of the chargers are not required to be adjusted during the production, thus improving the production efficiency and reducing the cost.

In the following, an apparatus for detecting a touch on a capacitive touch screen according to embodiments of the present disclosure is described in detail with reference to Figs. 3-5.

As shown in Fig. 3, the apparatus includes an exciting module 301, a first detecting module

302, a second detecting module 303, a switching module 304 and a control module 305. The exciting module 301 is configured to excite a plurality of row sensors and a plurality of column sensors in the capacitive touch screen. The first detecting module 302 is configured to detect a self-capacitance of the capacitive touch screen in real-time. The second detecting module 303 is configured to detect a mutual capacitance of the capacitive touch screen in real-time. The switching module 304 is connected with the first detecting module 302 and the second detecting module 303 respectively. The control module 305 is connected with the switching module 304, and configured to generate a control signal for controlling the switching module 304 to turn on or off the first detecting module 302 and the second detecting module 303 at different time, to determine that the capacitive touch screen is touched by a finger when a current self-capacitance changes with respect to a previous self-capacitance and a current mutual capacitance changes with respect to a previous mutual capacitance, and to determine that the capacitive touch screen is not touched by the finger when the current mutual capacitance changes with respect to the previous mutual capacitance but the current self-capacitance does not change with respect to the previous self-capacitance.

It should be noted that, the control module 305 generates the control signal to control the switching module 304 to turn on or off, so as to detect the self-capacitance and the mutual capacitance of the capacitive touch screen in the time-sharing mode. Specifically, the self-capacitance is detected firstly and then the mutual capacitance is detected. Alternatively, the mutual capacitance is detected firstly and then the self-capacitance is detected.

As shown in Fig. 4, the apparatus may further include a communicating module 306. Each detecting port of the capacitive touch screen is detected with the first detecting module 301 or the second detecting module 302, i.e., each detecting port of the plurality of row sensors Xl-Xn is connected with the first detecting module 302 and each detecting port of the plurality of column sensors Yl-Yn is connected with the second detecting module 303. The control module 305 receives information from a host computer via the communicating module 306 and generates the control signal to control the switching module 304 to turn on the first detecting module 302 and the second detecting module 303 at different time, so as to detect the self-capacitance and the mutual capacitance in the time-sharing mode.

Further, in some embodiments of the present disclosure, as shown in Fig. 5, the first detecting module 302 includes a first row detecting unit 3021 and a first column detecting unit 3022. The first row detecting unit 3021 is configured to detect a first sensing value of a row sensor when the row sensor is excited by the exciting module 301. The first column detecting unit 3022 is configured to detect a second sensing value of a column sensor when the column sensor is excited by the exciting module 301.

The second detecting module 303 includes a second row detecting unit 3031 and a second column detecting unit 3032. The second row detecting unit 3031 is configured to detect a third sensing value of each of the plurality of row sensors when each of the plurality of column sensors is excited by the exciting module 301. The second column detecting unit 3032 is configured to detect a fourth sensing value of each of the plurality of column sensors when each of the plurality of row sensors is excited by the exciting module 301.

When the control module 305 determines that the capacitive touch screen is touched by the finger, it can further determine a location touched by the finger. Specifically, the control module 305 determines a row corresponding to the row sensor having the first sensing value larger than a predetermined value as a self-capacitance positioning row, and determines a column corresponding to the column sensor having the second sensing value larger than the predetermined value as a self-capacitance positioning column. Thus, the control module 305 obtains the self-capacitance positioning result according to the self-capacitance positioning row and the self-capacitance positioning column. For example, when the exciting module 301 excites each of row sensors Xl-Xn, the first row detecting unit 3021 detects the first sensing values of the row sensors Xl-Xn, and if the first sensing values of the row sensors X5, X6 and X9 are larger than the predetermined value, the control module 305 determines the rows corresponding to the row sensors X5, X6 and X9 as the self-capacitance positioning rows. When the exciting module 301 excites each of column sensors Yl-Yn, the first column detecting unit 3022 detects the second sensing values of the column sensors Yl-Yn, and if the second sensing values of the column sensors Y4, Y7 and Y9 are larger than the predetermined value, the control module 305 determines the columns corresponding to the column sensors Y4, Y7 and Y9 as the self-capacitance positioning columns. Thus, the control module 305 determines coordinates of the nine intersection points between rows corresponding to the row sensors X5, X6 and X9 and columns corresponding to the column sensors Y4, Y7 and Y9 as the self-capacitance positioning result.

Next, the control module 305 determines an intersection point between a column corresponding to the column sensor having the third sensing value larger than the predetermined value and a row corresponding to a correspondingly excited row sensor as a mutual capacitance positioning point, or determines an intersection point between a row corresponding to the row sensor having the fourth sensing value larger than the predetermined value and a column corresponding to a correspondingly excited column sensor as a mutual capacitance positioning point. For example, when the exciting module 301 excites the row sensor XI, the second column detecting unit 3032 detects the third sensing values of the column sensors Yl-Yn, and if the column sensors Yl, Y3, Y5 and Y8 have the third sensing value larger than the predetermined value, intersection points between columns corresponding to the column sensors Yl, Y3, Y5, Y8 and rows corresponding to the row sensor XI are determined as mutual capacitance positioning points. In turn, the exciting module 301 excites the row sensors X2-Xn respectively, the second column detecting unit 3032 detects third sensing values of the column sensors Yl-Yn when each of the row sensors X2-Xn is excited, and intersection points between columns corresponding to the column sensors having the third sensing value larger than the predetermined value and rows corresponding to the correspondingly excited row sensor are determined as mutual capacitance positioning points. Alternatively, when the exciting module 301 excites the column sensor Yl, the second row detecting unit 3031 detects fourth sensing values of the row sensors Xl-Xn, and if the row sensors X3, X5, X6 and X8 have the fourth sensing values larger than the predetermined value, intersection points between rows corresponding to the row sensors X3, X5, X6, X8 and columns corresponding to the column sensor Yl are determined as mutual capacitance positioning points. In turn, the exciting module 301 excites the column sensors Y2-Yn respectively, the second row detecting unit 3031 detects the fourth sensing values of the row sensors Xl-Xn when each of the column sensors Y2-Yn is excited, and intersection points between rows corresponding to the row sensors having the fourth sensing values larger than the predetermined value and columns corresponding to the correspondingly excited column sensor are determined as mutual capacitance positioning points.

In one embodiment of the present disclosure, after obtaining the mutual capacitance positioning points, the control module 305 obtains mutual capacitance positioning coordinates, i.e. the mutual capacitance positioning result, according to the mutual capacitance positioning points.

Finally, the control module 305 determines the location touched by the finger according to the mutual capacitance positioning result and the self-capacitance positioning result. Specifically, the control module 305 compares a row of the mutual capacitance positioning coordinate with the self-capacitance positioning row, compares a column of the mutual capacitance positioning coordinate with the self-capacitance positioning column, and determines the mutual capacitance positioning point as the location touched by the finger when the row of the mutual capacitance positioning coordinate is the same as the self-capacitance positioning row or the column of the mutual capacitance positioning coordinate is the same as the self-capacitance positioning column. It should be noted that, since there is an error during detection or calculation, when the row of the mutual capacitance positioning coordinate is substantially the same as the self-capacitance positioning row and the column of the mutual capacitance positioning coordinate is substantially the same as the self-capacitance positioning column, the mutual capacitance positioning point can be determined as the location touched by the finger.

In another embodiment of the present disclosure, the control module 305 may be further configured to determine whether there is an interference on the capacitive touch screen according to a change between the current mutual capacitance and the previous mutual capacitance when the current self-capacitance does not change with respect to the previous self-capacitance.

For example, compared with a situation that there is not any touch or any interference on the capacitive touch screen, if the self-capacitance does not change but the mutual capacitance increases, the control module 305 can determines that there is water or other conductive objects such as a coin on the capacitive touch screen. Subsequently, if the self-capacitance does not change but the mutual capacitance decreases, the control module 305 can determine that the water is wiped away or the conductive objects are removed from the touch screen. If the self-capacitance does not change but a relatively large noisy data occasionally occurs to the mutual capacitance, the control module 305 determines that the charger interferes with the capacitive touch screen. In addition, when it is determined that there is an interference on the capacitive touch screen, the control module 305 sends interference information to the host computer via the communicating module 306, such that the host computer can run a corresponding anti-interference algorithm to protect the touch screen from interference. For example, when there is water or other conductive objects such as the coin on the capacitive touch screen, the control module 305 sends the interference information to the host computer and the host computer runs a waterproofing algorithm to improve the waterproof capability of the capacitive touch screen. When the control module 305 determines there is an action of wiping the water away from the capacitive touch screen, it sends the interference information to the host computer and the host computer updates the reference value of the mutual capacitance rapidly to adapt to the interference. When the control module 305 determines that the noise increases, it sends the interference information to the host computer and the host computer sends an instruction to execute a frequency-hopping scanning or increase the predetermined value so as to improve the noisy immunity capability. Thus, it is possible to protect the capacitive touch screen from external interference, thus avoiding misjudgment, such as incorrect reporting, jumping, and non-reporting. In conclusion, with the apparatus for detecting a touch on a capacitive touch screen according to embodiments of the present disclosure, by making use of the first detecting module and the second detecting module to detect the self-capacitance and the mutual capacitance of the capacitive touch screen at different time, the control module can determine the location touched by the finger more accurately. In addition, the control module can further determine whether there is an interference on the capacitive touch screen according to the results of detecting the self- capacitance and the mutual capacitance, which avoids the water interference and the charger interference, thus improving the positioning accuracy of the capacitive touch screen. Furthermore, with the apparatus for detecting a touch on a capacitive touch screen according to the present disclosure, frequencies of the chargers are not required to be adjusted during the production, thus improving the production efficiency and reducing the cost.

Any procedure or method described in the flow charts or described in any other way herein may be understood to comprise one or more modules, portions or parts for storing executable codes that realize particular logic functions or procedures. Moreover, advantageous embodiments of the present disclosure comprises other implementations in which the order of execution is different from that which is depicted or discussed, including executing functions in a substantially simultaneous manner or in an opposite order according to the related functions. This should be understood by those skilled in the art which embodiments of the present disclosure belong to.

The logic and/or step described in other manners herein or shown in the flow chart, for example, a particular sequence table of executable instructions for realizing the logical function, may be specifically achieved in any computer readable medium to be used by the instruction execution system, device or equipment (such as the system based on computers, the system comprising processors or other systems capable of obtaining the instruction from the instruction execution system, device and equipment and executing the instruction), or to be used in combination with the instruction execution system, device and equipment. As to the specification, "the computer readable medium" may be any device adaptive for including, storing, communicating, propagating or transferring programs to be used by or in combination with the instruction execution system, device or equipment. More specific examples of the computer readable medium comprise but are not limited to: an electronic connection (an electronic device) with one or more wires, a portable computer enclosure (a magnetic device), a random access memory (RAM), a read only memory (ROM), an erasable programmable read-only memory (EPROM or a flash memory), an optical fiber device and a portable compact disk read-only memory (CDROM). In addition, the computer readable medium may even be a paper or other appropriate medium capable of printing programs thereon, this is because, for example, the paper or other appropriate medium may be optically scanned and then edited, decrypted or processed with other appropriate methods when necessary to obtain the programs in a electric manner, and then the programs may be stored in the computer memories.

It is understood that each part of the present disclosure may be realized by the hardware, software, firmware or their combination. In the above embodiments, a plurality of steps or methods may be realized by the software or firmware stored in the memory and executed by the appropriate instruction execution system. For example, if it is realized by the hardware, likewise in another embodiment, the steps or methods may be realized by one or a combination of the following techniques known in the art: a discrete logic circuit having a logic gate circuit for realizing a logic function of a data signal, an application- specific integrated circuit having an appropriate combination logic gate circuit, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

Those skilled in the art shall understand that all or parts of the steps in the above exemplifying method of the present disclosure may be achieved by commanding the related hardware with programs. The programs may be stored in a computer readable storage medium, and the programs comprise one or a combination of the steps in the method embodiments of the present disclosure when run on a computer.

In addition, each function cell of the embodiments of the present disclosure may be integrated in a processing module, or these cells may be separate physical existence, or two or more cells are integrated in a processing module. The integrated module may be realized in a form of hardware or in a form of software function modules. When the integrated module is realized in a form of software function module and is sold or used as an standalone product, the integrated module may be stored in a computer readable storage medium.

The storage medium mentioned above may be read-only memories, magnetic disks or CD, etc.

Reference throughout this specification to "an embodiment," "some embodiments," "an example," "a specific example," or "some examples," means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. The appearances of the phrases throughout this specification are not necessarily referring to the same embodiment or example of the present disclosure. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

Although explanatory embodiments have been shown and described, it would be appreciated by those skilled in the art that the above embodiments cannot be construed to limit the present disclosure, and changes, alternatives, and modifications can be made in the embodiments without departing from spirit, principles and scope of the present disclosure.

Claims

What is claimed is:

1. A method for detecting a touch on a capacitive touch screen, comprising:

detecting a self-capacitance and a mutual capacitance of the capacitive touch screen in real-time, wherein the self-capacitance and the mutual capacitance are detected in a time- sharing mode;

determining whether a current self-capacitance changes with respect to a previous self-capacitance and whether a current mutual capacitance changes with respect to a previous mutual capacitance;

determining that the capacitive touch screen is touched by a finger when the current self-capacitance changes with respect to the previous self-capacitance and the current mutual capacitance changes with respect to the previous mutual capacitance;

determining that the capacitive touch screen is not touched by the finger when the current self-capacitance does not change with respect to the previous self-capacitance.

2. The method according to claim 1, wherein detecting a self-capacitance of the capacitive touch screen comprises:

detecting a first sensing value of a row sensor when the row sensor is excited; and

detecting a second sensing value of a column sensor when the column sensor is excited.

3. The method according to claim 1, wherein detecting a mutual capacitance of the capacitive touch screen comprises:

detecting a third sensing value of each of a plurality of column sensors when a row sensor is excited; and

detecting a fourth sensing value of each of a plurality of row sensors when a column sensor is excited.

4. The method according to any of claims 1-3, further comprising:

determining a location touched by the finger.

5. The method according to claim 4, wherein determining a location touched by the finger comprises:

determining a self-capacitance positioning result according to a result of detecting the self-capacitance;

determining a mutual capacitance positioning result according to a result of detecting the mutual capacitance; and determining the location touched by the finger according to the self-capacitance positioning result and the mutual capacitance positioning result.

6. The method according to claim 5, wherein determining a self-capacitance positioning result according to a result of detecting the self-capacitance comprises:

determining a row corresponding to the row sensor having the first sensing value larger than a predetermined value as a self-capacitance positioning row; and

determining a column corresponding to the column sensor having the second sensing value larger than the predetermined value as a self-capacitance positioning column.

7. The method according to claim 5, wherein determining a mutual capacitance positioning result according to a result of detecting the mutual capacitance comprises:

determining an intersection point between a column corresponding to the column sensor having the third sensing value larger than the predetermined value and a row corresponding to a correspondingly excited row sensor as a mutual capacitance positioning point; or

determining an intersection point between a row corresponding to the row sensor having the fourth sensing value larger than the predetermined value and a column corresponding to a correspondingly excited column sensor as a mutual capacitance positioning point.

8. The method according to claim 7, wherein determining a mutual capacitance positioning result according to a result of detecting the mutual capacitance further comprises:

obtaining a mutual capacitance positioning coordinate according to the mutual capacitance positioning point.

9. The method according to claim 7 or 8, wherein determining the location touched by the finger comprises:

determining whether a row of the mutual capacitance positioning coordinate is the same as the self-capacitance positioning row or whether a column of the mutual capacitance positioning coordinate is the same as the self-capacitance positioning column; and

if yes, determining the mutual capacitance positioning point as the location touched by the finger.

10. The method according to claim 1, further comprising:

determining whether there is an interference on the capacitive touch screen according to a change between the current mutual capacitance and the previous mutual capacitance when the current self-capacitance does not change with respect to the previous self-capacitance.

11. An apparatus for detecting a touch on a capacitive touch screen, comprising: a first detecting module, configured to detect a self-capacitance of the capacitive touch screen in real-time;

a second detecting module, configured to detect a mutual capacitance of the capacitive touch screen in real-time;

a switching module, connected with the first detecting module and the second detecting module respectively; and

a control module, connected with the switching module, and configured to generate a control signal for controlling the switching module to turn on or off the first detecting module and the second detecting module at different time, to determine that the capacitive touch screen is touched by a finger when a current self-capacitance changes with respect to a previous self-capacitance and a current mutual capacitance changes with respect to a previous mutual capacitance, and to determine that the capacitive touch screen is not touched by the finger when the current self-capacitance does not change with respect to the previous self-capacitance.

12. The apparatus according to claim 11, further comprising:

an exciting module, configured to excite a plurality of row sensors and a plurality of column sensors in the capacitive touch screen.

13. The apparatus according to claim 12, wherein the first detecting module comprises:

a first row detecting unit, configured to detect a first sensing value of the row sensor when the row sensor is excited;

a first column detecting unit, configured to detect a second sensing value of the column sensor when the column sensor is excited.

14. The apparatus according to claim 12, wherein the second detecting module comprises: a second row detecting unit, configured to detect a third sensing value of each of the plurality of row sensors when each of the plurality of column sensors is excited; and

a second column detecting unit, configured to detect a fourth sensing value of each of the plurality of column sensors when each of the plurality of row sensors is excited.

15. The apparatus according to any of claims 11-14, wherein the control module is further configured to determine a location touched by the finger.

16. The apparatus according to claim 15, wherein the control module is configured to:

determine a row corresponding to the row sensor having the first sensing value larger than a predetermined value as a self-capacitance positioning row;

determine a column corresponding to the column sensor having the second sensing value larger than the predetermined value as a self-capacitance positioning column;

determine an intersection point between a column corresponding to the column sensor having the third sensing value larger than the predetermined value and a row corresponding to a correspondingly excited row sensor as a mutual capacitance positioning point; or determine an intersection point between a row corresponding to the row sensor having the fourth sensing value larger than the predetermined value and a column corresponding to a correspondingly excited column sensor as a mutual capacitance positioning point;

obtain a mutual capacitance positioning coordinate according to the mutual capacitance positioning point; and

determine the mutual capacitance positioning point as the location touched by the finger when a row of the mutual capacitance positioning coordinate is the same as the self-capacitance positioning row or a column of the mutual capacitance positioning coordinate is the same as the self-capacitance positioning column.

17. The apparatus according to any of claims 11-16, further comprising:

a communicating module, wherein the control module communicates with a host computer via the communicating module, such that the control module receives information from the host computer to generate the control signal, and sends interference information to the host computer according to a change between the current mutual capacitance and the previous mutual capacitance when the current self-capacitance does not change with respect to the previous self-capacitance.