Patent Publication Number: US-2011067933-A1

Title: Touch-control apparatus

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present invention relates to a touch-control apparatus. 
     2. Related Art 
     Recently, the multi-media messages (MMS) are widely used, so the inquiring function for them is indispensable. In the latest electronic devices, the touch screen is adopted to replace the conventional input tools such as the mouse and keyboard. This is because the touch screen is an easy operated, human friendly and space saving input tool. In fact, the touch screen has been widely used in many applications, such as the tour guide system, automatic teller machine (ATM), personal digital assistant (PDA), mobile phone, notebook computer, point-on-sale (POS) terminal, and industrial control system (ICS). 
       FIG. 1  is a schematic view of a conventional touch-control apparatus  1 , which includes a touch-control unit  11  and a sensing unit  12 . The sensing unit  11  has a touch-control substrate  111 , at least one touch-control electrode layer  112 , an insulation layer  113  and an electrical shielding layer  114 . As shown in  FIG. 1 , the touch-control electrode layer  112  is disposed between the touch-control substrate  111  and the insulation layer  113 , and the insulation layer  113  is disposed between the touch-control electrode layer  112  and the electrical shielding layer  114 . The sensing unit  12  is electrically connected with the touch-control electrode layer  112  of the touch-control unit  11  for reading the voltage of an end A of the touch-control electrode layer  112 . Then, the read voltage is compared with a reference voltage to determine whether the touch-control apparatus  1  is pressed. 
       FIG. 2  is a waveform diagram of the conventional touch-control apparatus  1 . Referring to  FIGS. 1 and 2 , during a sensing period, the touch-control apparatus  1  charges the capacitances of the sensing conductive bars in the touch-control electrode layer  112  to a reference voltage V 2  in advance, and then performs the sensing procedure to determine whether the touch-control apparatus  1  is pressed or not by the way of reading the voltages of the capacitances. However, as shown in  FIG. 2 , the conventional touch-control apparatus  1  can not charge the capacitances of the sensing conductive bars to the reference voltage V 2  during the sensing period. In other words, the time period t 1  for charging the capacitances to the reference voltage V 2  is too long, so that the sensing procedure may be failed and the sensing efficiency is poor. Therefore, it is an important object of the present invention to provide a touch-control apparatus with enhanced sensing efficiency. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing, an object of the present invention is to provide a touch-control apparatus having the enhanced sensing efficiency. 
     To achieve the above, the present invention discloses a touch-control apparatus including a touch-control unit, a sensing unit and an auxiliary voltage supplying unit. The touch-control unit includes a touch-control substrate and at least one touch-control electrode layer, which is disposed on a surface of the touch-control substrate. The sensing unit is connected with the touch-control electrode layer of the touch-control unit and outputs a charging signal to a sensing conductive bar of the touch-control electrode layer according to a power signal. The auxiliary voltage supplying unit is electrically connected with the sensing unit and the touch-control electrode layer of the touch-control unit for outputting an auxiliary charging signal to the sensing conductive bar. 
     In one embodiment of the invention, the auxiliary charging signal is a DC signal. 
     In one embodiment of the invention, the charging signal is a DC signal. 
     In one embodiment of the invention, the auxiliary voltage supplying unit includes a resistor electrically connected with the sensing unit and the touch-control electrode layer. 
     In one embodiment of the invention, the auxiliary voltage supplying unit further includes an amplifier coupled with the resistor. 
     In one embodiment of the invention, the auxiliary voltage supplying unit and the sensing unit provide the auxiliary voltage signal and the charging signal, respectively and simultaneously, to the sensing conductive bar. 
     In one embodiment of the invention, the auxiliary charging signal provides a pre-determined level to the sensing conductive bar. 
     In addition, the present invention also discloses a detecting method of a touch-control apparatus, which includes a touch-control unit, a sensing unit and an auxiliary voltage supplying unit. The detecting method includes the following steps of: outputting a charging signal to a sensing conductive bar of a touch-control electrode layer of the touch-control unit according to a power signal by the sensing unit; outputting an auxiliary charging signal to the sensing conductive bar by the auxiliary voltage supplying unit; and reading a voltage of an end of the sensing conductive bar by the sensing unit. 
     In one embodiment of the invention, the detecting method further includes the following steps of: transmitting the read voltage to an input terminal of a comparator, and comparing the read voltage and a reference voltage by the comparator so as to output a signal to a timer. 
     In one embodiment of the invention, the auxiliary voltage supplying unit and the sensing unit provide the auxiliary voltage signal and the charging signal, respectively and simultaneously, to the sensing conductive bar. 
     In one embodiment of the invention, the step of outputting the auxiliary charging signal to the touch-control electrode layer by the auxiliary voltage supplying unit is prior to the step of outputting the charging signal to the sensing conductive bar. 
     As mentioned above, the touch-control apparatus of the present invention has a sensing unit for outputting the charging signal to the sensing conductive bar of the touch-control electrode layer of the touch-control unit and an auxiliary voltage supplying unit for outputting the auxiliary charging signal to the sensing conductive bar. Thus, the capacitances of the sensing conductive bar can reach the desired reference voltage much faster. Then, the sensing unit can determine whether the touch-control apparatus is pressed according to the charging time. Accordingly, the touch-control apparatus of the present invention can increase the charging speed of the capacitances of the sensing conductive bar, so that the sensing efficiency of the touch-control apparatus can be enhanced. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the subsequent detailed description and accompanying drawings, which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
         FIG. 1  is a schematic view of a conventional touch-control apparatus; 
         FIG. 2  is a waveform of the conventional touch-control apparatus; 
         FIG. 3  is a schematic view of a touch-control apparatus according to an embodiment of the present invention; 
         FIG. 4  is a circuit diagram of the touch-control apparatus according to the embodiment of the present invention; 
         FIG. 5  is a schematic view of another touch-control apparatus according to the embodiment of the present invention; 
         FIG. 6  is a flow chart of a detecting method of the touch-control apparatus according to the embodiment of the present invention; 
         FIG. 7  is a waveform of the touch-control apparatus according to a first embodiment of the present invention; 
         FIG. 8  is a waveform of the touch-control apparatus according to a second embodiment of the present invention; and 
         FIG. 9  is a waveform of the touch-control apparatus according to a third embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements. 
     The touch-control apparatus of the present invention can cooperate with a display apparatus (not shown), such as a LCD display apparatus, an OLED display apparatus or an e-paper display apparatus. 
       FIG. 3  is a schematic view of a touch-control apparatus according to an embodiment of the present invention, and  FIG. 4  is a circuit diagram of the touch-control apparatus. With reference to  FIGS. 3 and 4 , a touch-control apparatus  2  according to an embodiment of the present invention includes a touch-control unit  21 , a sensing unit  22  and an auxiliary voltage supplying unit  23 , which is electrically connected with the touch-control unit  21  and the sensing unit  22 . 
     The touch-control unit  21  has a touch-control substrate  211 , at least one touch-control electrode layer, two insulating layers  213   a  and  213   b , and an electrical shielding layer  214 . The touch-control substrate  211 , which is made of glass or a plastic material, can protect the internal electronic elements and sense the press actions. The touch-control electrode layer is disposed on one surface of the touch-control substrate  211 . In this embodiment, the touch-control unit  21 , for example, has two touch-control electrode layers, i.e. a first touch-control electrode layer  212   a  and a second touch-control electrode layer  212   b . Each of the first and second touch-control electrode layers  212   a  and  212   b  includes a plurality of sensing conductive bars  6 , and the sensing conductive bars  6  of the first touch-control electrode layer  212   a  are perpendicular to those of the second touch-control electrode layer  212   b . The sensing electrodes  61  of the sensing conductive bars  6  of the first and second touch-control electrode layers  212   a  and  212   b  can be rhombic, square, circular, elliptic, polygonal or irregular. In the current embodiment, the sensing electrodes  61  are rhombic for example. Moreover, the first and second touch-control electrode layers  212   a  and  212   b  can be transparent thin-film conductive layers. The insulating layer  213   a  is disposed between the first and second touch-control electrode layers  212   a  and  212   b , and the insulating layer  213   b  is disposed between the second touch-control electrode layer  212   b  and the electrical shielding layer  214 . In the embodiment, the electrical shielding layer  214  is made of an electrical conductive material such as an ITO (indium tin oxide) thin film. To be noted, the touch-control apparatus  2  may be not configured with the electrical shielding layer  214  depending on different designs, and the touch-control apparatus  2  of this embodiment is configured with the electrical shielding layer  214  indeed. 
     The sensing unit  22  is electrically connected with the first and second touch-control electrode layers  212   a  and  212   b  of the touch-control unit  21 . In more detailed, the sensing unit  21  is electrically connected with the sensing conductive bars  6  of the first and second touch-control electrode layers  212   a  and  212   b . Referring to  FIG. 4 , several aspects of the sensing unit will be described hereinbelow, wherein some elements (e.g. the auxiliary voltage supplying unit) are omitted for concise purpose, and the auxiliary voltage supplying unit  23  is coupled to, for example, only one of the sensing conductive bars  6  in the following cases. In this embodiment, the sensing unit  22  receives a power signal V 1 , so that it then outputs a charging signal E 1 , which is a DC signal, to the touch-control electrode layers  212   a  and  212   b . As shown in  FIG. 4 , the sensing unit  22  has a first switch  221 , a second switch  222 , a resistor R, two capacitors C 1  and C 2 , a comparator  223  and a timer  224 . One terminal of the first switch  221  and one terminal of the second switch  222  are coupled with the touch-control electrode layer  212   a , the other terminal of the first switches  221  is grounded, and the other terminal of the second switch  222  is coupled with the auxiliary voltage supplying unit  23 . Thus, the first and second switches  221  and  222  can control the direction of the charging signal E 1 . If the charging signal E 1  should not be transmitted to the touch-control unit  21 , the first and second switches  221  and  222  are both open circuited, so that the charging signal E 1  can not be transmitted from the sensing unit  22  to the touch-control unit  21 . Two terminals of the resistor R are coupled with the capacitors C 1  and C 2 , respectively, and the resistor R and the capacitor C 2  can form a low-pass filter. An input terminal of the comparator  223  is coupled with one terminal of the resistor R and one terminal of the capacitor C 2 , and another input terminal of the comparator  223  is used to receive a reference voltage V 2 . An input terminal of the timer  224  is coupled with an output terminal of the comparator  223 , and another input terminal thereof is coupled with an oscillator  225 . The oscillator  225  can output a signal S 1 , which is a clock signal, to the timer  224 . To be noted, the structure aspect of the sensing unit  22  is used for illustration only and is not to limit the scope of the present invention. 
     With reference to  FIG. 3  again, the auxiliary voltage supplying unit  23  is electrically connected with the sensing unit  22  and the touch-control electrode layers  212   a  and  212   b  of the touch-control unit  21 . In more specific, the auxiliary voltage supplying unit  23  is electrically connected with the sensing conductive bars  6  of the sensing unit  22  and the touch-control electrode layers  212   a  and  212   b . In this embodiment, the auxiliary voltage supplying unit  23  receives an auxiliary power signal V 3  and then outputs an auxiliary charging signal E 2  to the touch-control electrode layers  212   a  and  212   b . Herein, the auxiliary power signal V 3  and the auxiliary charging signal E 2  are both DC signals. In addition, the auxiliary voltage supplying unit  23  includes at least one resistor R for electrically connecting with the sensing unit  22  and the touch-control electrode layers  212   a  and  212   b . In the current embodiment, the auxiliary voltage supplying unit  23  includes a plurality of resistors R, each of which is electrically connected with the sensing conductive bars  6  of the first and second touch-control electrode layers  212   a  and  212   b . To be noted, the charging signal E 1  and the auxiliary charging signal E 2  can be adjusted according to different designs. 
       FIG. 5  is a schematic view of another touch-control apparatus according to the embodiment of the present invention. Referring to  FIG. 5 , an auxiliary voltage supplying unit  23   a  may further include an amplifier  231  coupled with the resistor R. In this embodiment, the amplifier  231  is coupled with one sensing conductive bar  6  of the first touch-control electrode layer  212   a  for illustration only. The amplifier  231  can amplify the received auxiliary power signal V 3 , and then the auxiliary power signal V 3  is stepped down by the resistor R so as to output an auxiliary charging signal E 3  to the first touch-control electrode layer  212   a.    
     As shown in  FIG. 6 , the present invention further discloses a detecting method of a touch-control apparatus, which includes a touch-control unit, a sensing unit and an auxiliary voltage supplying unit. The detecting method includes the steps W 1  to W 4 . The details and flow of the detecting method of the touch-control apparatus of the present invention will be described hereinafter with reference to  FIGS. 3 ,  4  and  6 . 
     In the step W 1 , the sensing unit  22  receives a power signal V 1  and then outputs a charging signal E 1  to the touch-control electrode layers  212   a  and  212   b  of the touch-control unit  21  for charging the capacitances of the sensing conductive bars  6  of the touch-control electrode layers  212   a  and  212   b . In addition, the step W 1  the auxiliary voltage supplying unit  23  further receives an auxiliary power signal V 3 , which is stepped down by a resistor R, and then the auxiliary voltage supplying unit  23  outputs an auxiliary charging signal E 2  to the touch-control electrode layers  212   a  and  212   b  of the touch-control unit  21  for charging the capacitances of the sensing conductive bars  6  of the touch-control electrode layers  212   a  and  212   b . Since the touch-control apparatus  2  reads the touch-control status by way of continuously scanning, the charging signal E 1  and the auxiliary charging signal E 2  can be transmitted to the to-be-detected sensing conductive bar  6  at the same time period or adjacent two time periods. In this case, the charging signal E 1  and the auxiliary charging signal E 2  are transmitted to one of the sensing conductive bars  6  of the first touch-control electrode layer  212   a.    
     In the step W 2 , the sensing unit  22  reads a voltage of one end B of the sensing conductive bar  6  of the first touch-control electrode layer  212   a . After passing through a low-pass filter consisting of the resistor R and capacitor C 2 , the voltage is transmitted to the input terminal of a comparator  223  of the sensing unit  22 . Then, the comparator  223  can compare the read voltage with a reference voltage V 2 . If the read voltage is equal to the reference voltage V 2 , a signal S 2  is then transmitted to a timer  224 . In addition, an oscillator  225  outputs a signal S 1 , and the timer  224  starts counting according to the signal S 1  when the charging signal E 1  and the auxiliary charging signal E 2  are inputted to the touch-control electrode layers  212   a  and  212   b . When the voltage read by the comparator  223  is equal to the reference voltage V 2 , the comparator  223  transmits a signal S 2  to the timer  224  to stop counting. Then, the sensing unit  22  can calculate to obtain a capacitance value according to the current flowing through the sensing conductive bar  6  during the counted time period. The obtained capacitance value and the charging time are in direct proportion, and the obtained capacitance value can represent the capacitance of the sensing conductive bar  6  or the sum of the capacitance of the sensing conductive bar  6  and the capacitance generated as the touch-control apparatus  2  is pressed. 
     In the step W 3 , the sensing unit  22  compares the detected capacitance value and the capacitance value as the touch-control apparatus  2  is not pressed to determine the touch-control status of the touch-control apparatus  2 . 
       FIG. 7  is a waveform diagram of a touch-control apparatus according to a first embodiment of the present invention, wherein the solid line represents the waveform of the touch-control apparatus of the present invention and the dotted line represents the waveform of the conventional touch-control apparatus. The waveform diagram is obtained by measuring the voltage of one end of the sensing conductive bar of the touch-control electrode layer. In the present embodiment, the auxiliary voltage supply unit of the touch-control apparatus outputs an auxiliary charging signal E 4  to the sensing conductive bar of the touch-control electrode layer of the touch-control unit in advance so as to provide a pre-determined level to the sensing conductive bar, and then the sensing unit outputs the charging signal to the sensing conductive bar of the touch-control electrode layer of the touch-control unit. Accordingly, the capacitance of the to-be-detected sensing conductive bar can be charged. After that, the sensing unit detects a time period for the end when the voltage reaches the reference voltage V 2  so as to calculate a capacitance value of the sensing conductive bar based on the detected time period. Then, the touch-control status can be determined according to the calculated capacitance value. As shown in  FIG. 7 , the conventional touch-control apparatus needs the time period t 1  to charge the voltage of the sensing conductive bar to the reference voltage V 2 , and the touch-control apparatus of the present embodiment needs the time period t 2 , which is shorter than the time period t 1 , to do the same thing. Thus, the sensing speed of the touch-control apparatus of the present invention is increased. 
       FIG. 8  is a waveform diagram of a touch-control apparatus according to a second embodiment of the present invention, wherein the solid line represents the waveform of the touch-control apparatus of the present invention and the dotted line represents the waveform of the conventional touch-control apparatus. The waveform diagram is obtained by measuring the voltage of one end of the sensing conductive bar of the touch-control electrode layer. In the present embodiment, the auxiliary voltage supply unit of the touch-control apparatus outputs an auxiliary charging signal E 5  to the sensing conductive bar of the touch-control electrode layer of the touch-control unit in advance so as to provide a pre-determined level to the sensing conductive bar, and then the sensing unit outputs the charging signal to the sensing conductive bar of the touch-control electrode layer of the touch-control unit. Accordingly, the capacitance of the to-be-detected sensing conductive bar can be charged. The touch-control apparatus of the present embodiment charges the capacitance during a predetermined time period so as to precisely charge the capacitance to the reference voltage V 2 . If the voltage of the charged capacitance is greater than or less than the reference voltage V 2  during this predetermined time period, a current valve provided by the sensing unit for the next charging procedure will be modified. In addition, the sensing unit detects the voltage of the end to obtain the current value therethrough provided by the sensing unit when the detected voltage reaches a reference voltage V 2  during the predetermined time period. Then, a capacitance value of the sensing conductive bar can be calculated based on the current value. Thus, the touch-control status can be determined according to the capacitance value of the sensing conductive bar. As shown in  FIG. 8 , during a first time period t 31 , the auxiliary voltage supplying unit of the second embodiment outputs the auxiliary charging signal E 5  to the sensing conductive bar of the touch-control electrode layer for providing a pre-determined level to the sensing conductive bar of the touch-control electrode layer, and the sensing unit outputs a charging signal with a first level to the sensing conductive bar of the touch-control electrode layer. However, during the first time period t 31 , the charging signal and the auxiliary charging signal E 5  can not precisely increase the voltage of the to-be-detected sensing conductive bar to reach the reference voltage V 2 , so the charging signal must be adjusted. During the second time period t 32 , the auxiliary voltage supplying unit continuously outputs the auxiliary charging signal E 5  to the sensing conductive bar of the touch-control electrode layer for providing the pre-determined level to the touch-control electrode layer, and the sensing unit outputs a charging signal with a second level to the sensing conductive bar of the touch-control electrode layer. However, during the second time period t 32 , the capacitance of the to-be-detected sensing conductive bar is over-charged by the charging signal and the auxiliary charging signal E 5 , so the voltage thereof is higher than the reference voltage V 2 . Thus, the charging signal must be adjusted again. During the third time period t 33 , the auxiliary voltage supplying unit continuously outputs the auxiliary charging signal E 5  to the sensing conductive bar of the touch-control electrode layer for providing the pre-determined level to the touch-control electrode layer, and the sensing unit outputs a charging signal with a third level to the sensing conductive bar of the touch-control electrode layer. During the third time period t 33 , the capacitance of the to-be-detected sensing conductive bar is precisely charged by the charging signal and the auxiliary charging signal E 5  to reach the reference voltage V 2 . As shown in  FIG. 8 , the conventional touch-control apparatus reaches the reference voltage V 2  during the fourth time period t 34 , which means that the conventional touch-control apparatus needs four charging procedures to make the capacitance of the sensing conductive bar reach the reference voltage V 2 . In contrast, the touch-control apparatus of the present invention can make the capacitance of the sensing conductive bar precisely reach the reference voltage V 2  by three charging procedures. Thus, the touch-control apparatus of the present invention can reach the reference voltage V 2  with shorter time than the conventional one, so that the sensing speed of the touch-control apparatus of the present invention is increased. 
       FIG. 9  is a waveform diagram of a touch-control apparatus according to a third embodiment of the present invention, wherein the solid line represents the waveform of the touch-control apparatus of the present invention and the dotted line represents the waveform of the conventional touch-control apparatus. The waveform diagram is obtained by measuring the voltage of one end of the touch-control electrode layer. In the present embodiment, the auxiliary voltage supply unit and the sensing unit of the touch-control apparatus output an auxiliary charging signal and a charging signal to the sensing conductive bar of the touch-control electrode layer of the touch-control unit, respectively and simultaneously, so as to charge the capacitance of the to-be-detected sensing conductive bar. Since the auxiliary charging signal and the charging signal are simultaneously transmitted to the sensing conductive bar of the touch-control electrode layer, the charging speed thereof can be accelerated. The touch-control apparatus of the present embodiment charges the capacitance during a predetermined time period so as to precisely charge the capacitance of the sensing conductive bar to the reference voltage V 2 . If the voltage of the charged capacitance is greater than or less than the reference voltage V 2  during this time period, the voltage for the next charging procedure will be modified, so that the voltage of the capacitance can precisely reach the reference voltage V 2 . In addition, the sensing unit detects the voltage of the end to obtain a current value therethrough simultaneously provided by the auxiliary voltage supplying unit and the sensing unit when the detected voltage reaches a reference voltage V 2  during the predetermined time period. Then, a capacitance value of the sensing conductive bar can be calculated based on the current value. Thus, the touch-control status can be determined according to the capacitance value of the sensing conductive bar. As shown in  FIG. 9 , during a first time period t 41 , the auxiliary voltage supplying unit and the sensing unit of the third embodiment respectively output an auxiliary charging signal with a first level and a charging signal to the sensing conductive bar of the touch-control electrode layer, simultaneously. However, during the first time period t 41 , the charging signal and the auxiliary charging signal can not precisely increase the voltage of the capacitance of the to-be-detected sensing conductive bar to reach the reference voltage V 2 , so the auxiliary charging signal must be adjusted. During the second time period t 42 , the auxiliary voltage supplying unit and the sensing unit respectively output an auxiliary charging signal with a second level and a charging signal to the touch-control electrode layer, simultaneously. However, during the second time period t 42 , the capacitance of the to-be-detected sensing conductive bar is over-charged by the charging signal and the auxiliary charging signal, so the voltage thereof is higher than the reference voltage V 2 . Thus, the auxiliary charging signal must be adjusted again. During the third time period t 43 , the auxiliary voltage supplying unit and the sensing unit respectively output an auxiliary charging signal with a third level and a charging signal to the sensing conductive bar of the touch-control electrode layer, simultaneously. During the third time period t 43 , the capacitance of the to-be-detected sensing conductive bar is precisely charged by the charging signal and the auxiliary charging signal to reach the reference voltage V 2 . As shown in  FIG. 9 , the conventional touch-control apparatus reaches the reference voltage V 2  during the fourth time period t 44 , which means that the conventional touch-control apparatus needs four charging procedures to make the capacitance of the sensing conductive bar reach the reference voltage V 2 . In contrast, the touch-control apparatus of the present invention can make the capacitance of the sensing conductive bar precisely reach the reference voltage V 2  by three charging procedures. Thus, the touch-control apparatus of the present invention can reach the reference voltage V 2  with shorter time than the conventional one, so that the sensing speed of the touch-control apparatus of the present invention is increased. 
     In summary, the touch-control apparatus of the present invention has a sensing unit for outputting the charging signal to the sensing conductive bar of the touch-control electrode layer of the touch-control unit and an auxiliary voltage supplying unit for outputting the auxiliary charging signal to the sensing conductive bar of the touch-control electrode layer, respectively or simultaneously. Thus, the capacitances of the touch-control unit can reach the desired reference voltage much faster. Since the capacitance value and the charging time are in direct proportion, the sensing unit can determine whether the touch-control apparatus is pressed according to the charging time. Accordingly, the touch-control apparatus of the present invention can increase the charging speed of the capacitances of the sensing conductive bar, so that the sensing efficiency of the touch-control apparatus can be enhanced. 
     Although the present invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments, will be apparent to persons skilled in the art. It is, therefore, contemplated that the appended claims will cover all modifications that fall within the true scope of the present invention.