Abstract:
A sensing method for detecting a sensing array is provided. The sensing array comprises at least one sensing row. The sensing method comprises the steps of: obtaining a sensing curve according to a plurality of sensing data signals extracting from the sensing row; determining whether a curve feature of the sensing curve matches one of a plurality of predetermined curve features; and obtaining a touch condition of the sensing row according to the determination result related to the sensing row. A sensing device is further provided. The present invention can reduce the impact of interference noise on detection of a sensing array, and enhance accuracy of detecting a touch condition of the sensing array.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This application claims the benefit of China application No. 201110244537.9, filed on Aug. 21, 2011. 
         [0002]    1. Field of the Invention 
         [0003]    The invention relates to touch sensing technique, and more particularly to a touch sensing method and touch sensing device for a sensing array. 
         [0004]    2. Description of the Related Art 
         [0005]      FIG. 1A  shows a sensing row of a touch sensing array, which has been touched by one single object. Referring to  FIG. 1A , a sensing row  10  comprises a plurality of sensing cells C 1 - 1 ˜C 1 - 14  disposed in a line. Generally, one touch sensing operation for the sensing row  10  causes one series of sensing data signals read from the sensing row  10 . For example, when one single object  11  (such as a finger, that is one single touch point) touches a position near the sensing cells C 1 - 6  and C 1 - 7  in the sensing row  10 , the intensity of the sensing data signals read from the sensing cells C 1 - 1 ˜C 1 - 14  can be represented by a Gaussian Curve. In some applications, the sensing row  10  may be touched by a plurality of objects. Referring to  FIG. 2 , one object  20  touches a position near the sensing cells C 1 - 4  in the sensing row  10 , while another object touches a position near the sensing cells C 1 - 8  in the sensing row  10 . The intensity of the sensing data signals read from the sensing cells C 1 - 1 ˜C 1 - 14  can be represented by two Gaussian Curves. 
         [0006]    In prior arts, according to Gaussian Curve, real data generated when the sensing row  10  is touched can be distinguished from interference noise. Generally, a minimum threshold value is set to determine read data. However, if the touched area on the sensing row  10  is relatively small, the real data generated when the sensing row  10  is touched, may be treated as the interference noise. Thus, in this situation, the setting of the minimum threshold value for Gaussian Curve becomes a moot purpose. 
         [0007]    Thus, it is desired to provide a touch sensing method and touch sensing devices that can accurately detect a touch condition of a sensing array, such as a position of an object touching the sensing array. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    An exemplary embodiment of a sensing method for detecting a sensing array is provided. The sensing array comprises at least one sensing row. The sensing method comprises the following steps of: obtaining a sensing curve according to a plurality of sensing data signals extracting from the sensing row; determining whether a curve feature of the sensing curve matches with one of a plurality of predetermined curve features; and obtaining a touch condition of the sensing row according to the determination result related to the sensing row. 
         [0009]    In some embodiments, the plurality of sensing data signals represent capacitance values related to a plurality of sensing cells of the sensing row. Moreover, the touch condition of the sensing row comprises at least one of: whether the sensing row has been touched by at least one object, the number of objects touching the sensing row, a position of at least one object in the sensing row when the at least one object touches the sensing row, and/or a touch area in the sensing row when at least one object touches the sensing row. 
         [0010]    An exemplary embodiment of a sensing device for detecting a sensing array is provided. The sensing array comprises at least one sensing row. The sensing device comprises a calculation unit, a determination unit, and a detection unit. The calculation unit obtains a sensing curve according to a plurality of sensing data signals extracting from the sensing row. The determination unit determines whether a curve feature of the sensing curve matches with one of a plurality of predetermined curve features. The detection unit obtains a touch condition of the sensing array, according to the determination result, related to the selected sensing row. In some embodiments, the plurality of sensing data signals represent capacitance values related to the plurality of sensing cells of the sensing row. Moreover, the calculation unit calculates the difference between every two sensing data signals among the plurality of sensing data signals to obtain a plurality of differential values, and the determination unit obtains the sensing curve according to the plurality of differential values. 
         [0011]    In some other embodiments, the touch condition of the sensing row comprises at least one of: whether the sensing array has been touched by at least one object, the number of objects touching the sensing array, a coordinate of at least one object in the sensing array when the at least one object touches the sensing array, and/or a touch area in the sensing row when at least one object touches the sensing row. 
         [0012]    According to a touch sensing device and a touch sensing method, a feature of a sensing curve related to a sensing row to be detected can be compared with predetermined curve features. By the comparison of the curve features, the Impact of interference noise on detection of a sensing array can be reduced, and accuracy of detecting a touch condition of the sensing array can be enhanced. 
         [0013]    A detailed description is given in the following embodiments with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The invention can be more fully understood by reading the subsequent detailed description and examples, with references made to the accompanying drawings, wherein: 
           [0015]      FIG. 1  shows a sensing row of a touch sensing array which has been touched by a single object; 
           [0016]      FIG. 2  shows a sensing row of a touch sensing array which has been touched by two objects; 
           [0017]      FIG. 3  shows an exemplary embodiment of a sensing device; 
           [0018]      FIG. 4  shows an exemplary embodiment of a sensing array in  FIG. 3 ; 
           [0019]      FIGS. 5A-5C  show a touch condition of a sensing row, differential values and a profile form corresponding to the touch condition; 
           [0020]      FIGS. 6A˜6B ,  7 A˜ 7 B,  8 A˜ 8 B,  9 A˜ 9 B,  10 A˜ 10 B, and  11 A˜ 11 B show differential values and corresponding profile forms in differential types; 
           [0021]      FIG. 12  shows a flow chart of an exemplary embodiment of a sensing method; 
           [0022]      FIGS. 13A˜13C  show an exemplary embodiment of a touch condition of a sensing row and differential values, and a profile form corresponding to sensing data signals; and 
           [0023]      FIGS. 14A˜14C  show another exemplary embodiment of a touch condition of a sensing row and differential values, and a profile form corresponding to sensing data signals 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0024]    The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention, and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims. 
         [0025]      FIG. 3  shows an exemplary embodiment of a sensing device. Referring to  FIG. 3 , a sensing device  3  detects a touch condition applied to a sensing array  4 .  FIG. 4  shows an exemplary embodiment of a sensing array in  FIG. 3 . As shown in  FIG. 4 , the sensing array  4  comprises sensing rows  4 - 1 ˜ 4 -N (N is a positive integer), and each sensing row comprises a plurality of cells. For example, the sensing row  4 - 1  comprises sensing cells C 4 - 1 ˜C 4 -M (M is a positive integer). The sensing device  3  comprises a calculation unit  30 , a determination unit  31 , and a detection unit  32 . The determination unit  31  comprises a memory  310  for storing differential types of predetermined curve features and a curve processor  311 . In the embodiment, the predetermined curve features are profile forms, and the profile forms are obtained according to differential values that are not affected by interference noise. 
         [0026]      FIGS. 5A˜5C  show a touch condition of a sensing row and differential values, and a profile form corresponding to the touch condition.  FIG. 5A  shows a touch condition of a sensing row  5 . Assume that the sensing row  5  has a plurality of sensing cells C 5 - 1 ˜C 5 -M. In a case that the detection of the touch condition is not affected by interference noise, when one single object  50  (such as a finger, that is one single touch point) touches a position corresponding to the sensing cell C 5 - 6  in the sensing row  5 , the intensity of the sensing data signals read from the sensing cells C 5 - 1 ˜C 5 -M can be represented by a Gaussian Curve G 50 . At this time, a plurality of differential values is obtained according to the difference between every two sensing data signals among the sensing data signals. The differential values D 5 - 1 ˜D 5 - 4  shown in  FIG. 5B  are the meaningful differential values when one single object  50  touches the sensing row  5 . For example, the differential value D 5 - 1  is the difference between the sensing data signals of the sensing cells C 5 - 5  and C 5 - 6 , and the differential value D 5 - 2  is the difference between the sensing data signals of the sensing cells C 5 - 6  and C 5 - 7 . A sensing curve P 50  are obtained from the differential values D 5 - 1 ˜D 5 - 4 , as shown in  FIG. 5C . 
         [0027]    In the embodiment, the profile forms can be represented by the following six geometry symbols: 
         [0028]    (1) Regular triangle ▴: represents a full range, wherein corresponding differential values are all positive, and the differential values are increased and then decreased from the left to the right of the profile form. 
         [0029]    (2) Inverted regular triangle ▾: represents full range, wherein corresponding differential values are all negative, and the differential values are decreased and then increased from the left to the right of the profile form. 
         [0030]    (3) Right-angled triangle          : represents a half range, wherein corresponding differential values are all positive, and the differential values are decreased from the left to the right of the profile form. 
         [0031]    (4) Inverted right-angled triangle          : represents a half range, wherein corresponding differential values are all negative, and the differential values are increased from the left to the right of the profile form. 
         [0032]    (5) Two regular triangles ▴▴: represents two peak points of two full ranges, wherein corresponding differential values are all positive. 
         [0033]    (6) Two inverted regular triangles ▾▾: represents two peak points of two full ranges, wherein corresponding differential values are all negative. 
         [0034]    Referring to  FIGS. 5B˜5C , when one single touch point occurs (that is the touching of one single object  50 ), two negative differential values D 5 - 1 ˜D 5 - 2  and two positive values D 5 - 3  and D 5 - 4  are generated. In this case, a profile form of a sensing curve P 50  obtained from the differential values D 5 - 1 ˜D 5 - 4  is represented by                    . 
         [0035]    Referring to  FIGS. 6A˜6B , a series of differential values and a corresponding profile form in another type are shown. When one single touch point occurs, two negative differential values D 6 - 1 ˜D 6 - 2  and three positive values D 6 - 3  and D 6 - 5  are generated. In this case, a profile form of a sensing curve P 60  obtained from the differential values D 6 - 1 ˜D 6 - 5  is represented by          ▴. 
         [0036]    Referring to  FIGS. 7A and 7B , a series of differential values and a corresponding profile form in another type are shown. When one single touch point occurs, three negative differential values D 7 - 1 ˜D 7 - 3  and two positive values D 7 - 4  and D 7 - 5  are generated. In this case, a profile form of a sensing curve P 70  obtained from the differential values D 7 - 1 ˜D 7 - 5  is represented by ▴         . 
         [0037]    Referring to  FIGS. 8A and 8B , a series of differential values and a corresponding profile form in another type are shown. When one single touch point occurs, three negative differential values D 8 - 1 ˜D 8 - 3  and three positive values D 8 - 4  and D 8 - 6  are generated. In this case, a profile form of a sensing curve P 80  obtained from the differential values D 8 - 1 ˜D 8 - 6  is represented by ▴▾. 
         [0038]    Referring to  FIGS. 9A and 9B , a series of differential values and a corresponding profile form in another type are shown. When two touch points occur, five negative differential values D 9 - 1 ˜D 9 - 5  and five positive values D 9 - 6  and D 9 - 10  are generated. In this case, a profile form of a sensing curve P 90  obtained from the differential values D 9 - 1 ˜D 9 - 10  is represented by ▾▾▴. According to  FIG. 9B , there are two peak points in the front half of the curve respectively corresponding to the differential values D 9 - 2  and D 9 - 5 . 
         [0039]    Referring to  FIGS. 10A and 10B , a series of differential values and a corresponding profile form in another type are shown. When two touch points occur, five negative differential values D 10 - 1 ˜D 10 - 5  and five positive values D 10 - 6  and D 10 - 10  are generated. In this case, a profile form of a sensing curve P 10  obtained from the differential values D 10 - 1 ˜D 10 - 10  is represented by ▾▴▴. According to  FIG. 10B , there are two peak points in the back half of the curve respectively corresponding to the differential values D 10 - 6  and D 10 - 8 . 
         [0040]    Referring to  FIGS. 11A and 11B , a series of differential values and a corresponding profile form in another type are shown. When two touch points occur, five negative differential values D 11 - 1 ˜D 11 - 5  and five positive values D 11 - 6  and D 11 - 10  are generated. In this case, a profile form of a sensing curve P 11  obtained from the differential values D 11 - 1 ˜D 11 - 10  is represented by ▾▾▴▴. According to  FIG. 11B , there are two peak points in the front half of the curve respectively corresponding to the differential values D 11 - 2  and D 11 - 5 , and there are two peak points in the back half of the curve respectively corresponding to the differential values D 11 - 6  and D 11 - 9 . 
         [0041]    The memory  310  of the determination unit  31  at least stores the profile forms P 50 , P 60 , P 70 , P 80 , P 90 , P 10 , and P 11  of  FIGS. 5B ,  6 B,  7 B,  8 B,  9 B,  10 B, and  11 B in advance to serve as predetermined profile forms. 
         [0042]      FIG. 12  shows an exemplary embodiment touch sensing method for the sensing device  3 . Referring to  FIGS. 3˜4  and  12 , the calculation unit  30  is coupled to the sensing array  4 . The calculation unit  30  selects one sensing row among the sensing rows  4 - 1 ˜ 4 -N to serve as a sensing row to be detected for a sensing operation (step S 10 ). For example, the sensing row  4 - 1  is selected to serve as a sensing row to be detected. The sensing operation performed to the sensing row  4 - 1  is described in the following. The calculation unit  30  extracts sensing data signals S 4 - 1 ˜S 4 -M from the sensing cells C 4 - 1 ˜C 4 -M in the sensing row  4 - 1  (step S 11 ). The sensing data signals S 4 - 1 ˜S 4 -M respectively represent capacitance values related to the sensing cells C 4 - 1 ˜C 4 -M. The capacitance values change with an object being approaching the sensing cells C 4 - 1 ˜C 4 -M. The calculation unit  30  calculates the difference between every two sensing data signals among the sensing data signals S 4 - 1 ˜S 4 -M to obtain differential values D 4 - 1 ˜D 4 -X (X is a positive integer, and 1&lt;x&lt;M) (step S 12 ). The calculation unit  30  obtains a sensing curve P 40  corresponding to the sensing row  4 - 1 , according to the differential values D 4 - 1 ˜D 4 -X (step S 13 ). 
         [0043]    For example, referring to  FIGS. 13A˜13C , an exemplary embodiment of a touch condition of a sensing row and differential values and a profile form corresponding to sensing data signals is shown. When one single object  130  (such as finger, that is one single touch point) touches a position near to the sensing cells C 4 - 6  and C 4 - 7  in the sensing row  5 - 1 , the intensity of the sensing data signals S 4 - 1 ˜S 4 -M read from the sensing cells C 4 - 1 ˜C 4 -M can be represented by a Gaussian Curve G 130 . The calculation unit  30  extracts sensing data signals S 4 - 1 ˜S 4 -M from the sensing cells C 4 - 1 ˜C 4 -M in the sensing row  4 - 1  (step S 11 ) and calculates the difference between every two sensing data signals among the sensing data signals S 4 - 1 ˜S 4 -M to obtain the differential values D 4 - 1 ˜D 4 -X (step S 12 ). The differential values D 4 - 1 ˜D 4 - 5  shown in  FIG. 13B  are the meaningful differential values when one single object  130  touches the sensing row  4 - 1 . For example, the differential value D 4 - 1  is the difference between the sensing data signals S 4 - 5  and S 4 - 6  of the sensing cells C 4 - 5  and C 4 - 6 , and the differential value D 4 - 5  is the difference between the sensing data signals S 4 - 6  and S 4 - 7  of the sensing cells C 4 - 6  and C 4 - 7 . The calculation unit  30  obtains a sensing curve P 40  corresponding to the sensing row  4 - 1 , according to the differential values D 4 - 1 ˜D 4 - 5  (step S 13 ). As shown in  FIG. 13C , in the case, the profile form of the sensing curve P 40  is represented by          ▴. 
         [0044]    In some applications, the sensing row  4 - 1  may be touched by a plurality of objects. Referring to  FIGS. 14A˜14C , another exemplary embodiment of a touch condition of a sensing row and differential values and a profile form corresponding to sensing data signals is shown. For example, when one object  140  (such as a finger) touches a position near the sensing cells C 4 - 4  in the sensing row  4 - 1 , and another object  141  (such as an finger) touches a position near the sensing cells C 4 - 8  in the sensing row  10 , the intensity of the sensing data signals S 4 - 1 ˜S 4 -M read from the sensing cells C 4 - 1 ˜C 4 -M can be represented by two Gaussian Curves G 140  and G 141 . The calculation unit  30  extracts sensing data signals S 4 - 1 ˜S 4 -M from the sensing cells C 4 - 1 ˜C 4 -M in the sensing row  4 - 1  (step S 11 ) and calculates the difference between every two sensing data signals among the sensing data signals S 4 - 1 ˜S 4 -M to obtain the differential values D 4 - 1 ˜D 4 -X (step S 12 ). The differential values D 4 - 1 ˜D 4 - 10  shown in  FIG. 14B  are the meaningful differential values when the two objects  140  and  141  touch the sensing row  4 - 1 . For example, the differential value D 4 - 1  is the difference between the sensing data signals S 4 - 1  and S 4 - 2  of the sensing cells C 4 - 1  and C 4 - 2 . The calculation unit  30  obtains a sensing curve P 40  corresponding to the sensing row  4 - 1  according to the differential values D 4 - 1 ˜D 4 - 10  (step S 13 ). As shown in  FIG. 14C , in the embodiment, when the two objects  140  and  141  (that is two touch points) touch the sensing row  4 - 1 , there are two peak points in each of the two halves of the curve. For example, there are two peak points in the front half of the curve respectively corresponding to the differential values D 4 - 2  and D 4 - 5 , and there are two peak points in the back half of the curve respectively corresponding to the differential values D 4 - 7  and D 4 - 9 . However, in other cases (which two touch points occur), there are two peak points in only one of the two halves of the curve (the front or back of the curve). 
         [0045]    After the sensing curve corresponding to the sensing row  4 - 1  is obtained, the curve processor  311  of the determination unit  31  can perform a perfection operation to the sensing curve (step S 14 ). The perfection operation is not limited to conventional curve perfection manners (that is more obvious noise in the sensing curve is removed). In the embodiment, the curve processor  311  does not perform the perfection operation to each sensing curve. That is, the step S 14  can be omitted. Then, the determination unit  31  determines whether a profile form (         ▴/▾▾▴▴) of the sensing curve P 40  matches with one of the profile forms of the sensing curves P 50 . P 60 , P 70 , P 80 , P 90 , P 10 , and P 11  stored in the memory  310  (step S 15 ). When the determination unit  31  determinates that the profile form of the sensing curve P 40  corresponding to the sensing row  4 - 1  matches with one of the profile forms of the sensing curves P 50 , P 60 , P 70 , P 80 , P 90 , P 10 , and P 11  stored in the memory  310 , the determination unit  31  notifies the detection unit  32  of the determination result. The determination result comprises that the sensing curve P 40  corresponding to the sensing row  4 - 1  matches with which one predetermined profile form. The detection unit  32  detects the touch condition of the sensing row  4 - 1  according to the determination result related to the sensing row  4 - 1  (step S 16 ). The touch condition of the sensing row  4 - 1  comprises whether the sensing row  4 - 1  has been touched by at least one object, the number of objects touching the sensing row  4 - 1 , a position of at least one object in the sensing row  4 - 1  when the at least one object touches the sensing row  4 - 1 , and/or a touched area in the sensing row  4 - 1  when at least one object touches the sensing row  4 - 1 . After, the sensing device  3  ends the sensing operation. 
         [0046]    For example, when the determination unit  31  determinates that the profile form of the sensing curve P 40 , corresponding to the sensing row  4 - 1 , matches with the profile form          ▴ of the sensing curve P 60  stored in the memory  310 , the detection unit  32  detects that the sensing row  4 - 1  is touched by one single object according to the determination result. As shown in  FIG. 13A , the object  130  touches a position near the sensing cells C 4 - 6  and C 4 - 7  in the sensing row  4 - 1 . Since the sensing curve P 40  is obtained according to the meaningful differential values D 4 - 1 ˜D 4 - 5 , the detection unit  32  can obtain a touched position and a touched area of the single object when the single object touches the sensing row  4 - 1 . 
         [0047]    In another example, when the determination unit  31  determinates that the profile form of the sensing curve P 40  corresponding to the sensing row  4 - 1  matches with the profile form ▾▾▴▴ of the sensing curve P 11  stored in the memory  310 , the detection unit  32  detects that the sensing row  4 - 1  is touched by two single objects according to the determination result. As shown in  FIG. 14A , the object  140  touches a position near the sensing cell C 4 - 4  in the sensing row  4 - 1 , while the object  141  touches a position near the sensing cell C 4 - 8  in the sensing row  4 - 1 . Since the sensing curve P 40  is obtained according to the meaningful differential values D 4 - 1 ˜D 4 - 10 , the detection unit  32  can obtain touched positions and touched areas of the two objects when the two objects touch the sensing row  4 - 1 . 
         [0048]    When the determination unit  31  determines that the profile form of the sensing curve corresponding to the sensing row  4 - 1  does not match one of the predetermined profile forms stored in the memory  310 , the sensing operation is ended. 
         [0049]    According to the above embodiment, after the determination unit  31  determines that the profile form of the sensing curve corresponding to the sensing row  4 - 1  does not match one predetermined profile forms stored in the memory  310  in the step S 15  and after the detection step S 16  for the sensing row  4 - 1 , the sensing operation is ended. In some embodiments, after the determination unit  31  determines that the profile form of the sensing curve corresponding to the sensing row  4 - 1  does not match one predetermined profile forms stored in the memory  310  in the step S 15 , and after the detection step S 16  for the sensing row  4 - 1 , the sensing method returns back to the step S 10 , and the calculation unit  30  can continuously select another sensing row among the sensing rows  4 - 2 ˜ 4 -N to serve as the sensing row to be detected, and the sensing operation is performed again. For example, the calculation unit  30  selects the sensing row  4 - 2  next to the sensing row  4 - 1  to serve as the sensing row to be detected. The calculation unit  30 , the determination unit  31 , and the detection unit  32  perforin the same operations as the steps S 11 ˜S 16 . When the detection unit  32  obtains the determination result related to at least two sensing rows among the sensing rows  4 - 2 ˜ 4 -N, some sensing rows among the sensing rows  4 - 2 ˜ 4 -N, or all of the sensing rows  4 - 2 ˜ 4 -N, the detection unit  32  can detect a touch condition of the sensing array  4  according to the determination result. The touch condition of the sensing array  4  comprises whether the sensing array  4  has been touched by at least one object, the number of objects touching the sensing array  4 , a coordinate of at least one object in the sensing array  4  when the at least one object touches the sensing array  4 , and/or a touched area in the sensing array  4  when at least one object touches the sensing array  4 . 
         [0050]    According to the above description, the sensing device  3  stores several types of predetermined profile forms in advance to be compared with the profile form of the sensing curve of the sensing row to be detected. By the comparison of the profile forms, the impact of interference noise can be reduced. Moreover, the sensing device  3  of the embodiment does not set the minimum threshold value. Thus, when the touched area of the sensing array  4  is small, the touch condition of the sensing array  4  can be accurately detected. 
         [0051]    Moreover, according to the embodiments, when the size of an object that touched the sensing array  1  is larger (the size of the object is directly proportional to the touched area), and the distance between every two sensing cells in one sensing row is smaller, the sensing curve obtained by the determination unit  31  can conform to real touch operation of that the object touches the sensing cells more exactly, so that the touch condition of the sensing array  4 , which is detected according to the sensing curve, can be more accurate. 
         [0052]    While the invention has been described by way of example and in tennis of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.