Abstract:
A touch calibration system and method thereof are provided in the present invention. When a touch pad stops receiving a touch signal generated from a user to make the touch calibration system be at a calibration mode, a first step of the touch calibration method is providing a fixed count value to a counter of the touch calibration system. A second step is provided that a wave-generation module generates an oscillation wave, a counter counts an oscillation number corresponding to the oscillation wave, and a timer counts a calibration oscillation time. A third step is provided that determining whether the oscillation number achieves the fixed count value. When the oscillation number achieves the fixed count value, a storage module is received the calibration oscillation time to store the calibration oscillation time.

Description:
[0001]    This application claims the benefit of Taiwan Patent Application Serial No. 104126972, filed Aug. 19, 2015, the subject matter of which is incorporated herein by reference. 
       BACKGROUND OF INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention is related to a touch calibration system and a method thereof, and more particularly related to a touch calibration system and a method thereof by using a counter which is set with a fixed count value. 
         [0004]    2. Description of the Prior Art 
         [0005]    Attending with the progress of technology, the development of network has led to a life full of electronic devices, of which the interface of touch control is the main trend. In order to make sure that the touch control on the electronic devices can run smoothly without trouble, a test for the touch circuit is necessary. 
         [0006]    Please refer to  FIGS. 1 and 2 , wherein  FIG. 1  is a block diagram of a conventional touch calibration system, and  FIG. 2  is a diagram showing the oscillating wave of the conventional art. As shown, in the existed touch calibration system PA 1 , a waveform generation module PA 12  is electrically connected to a touch pad PA 11 , a counter PA 13  is electrically connected to the waveform generation module PA 12 , a timer PA 14  is electrically connected to the counter PA 13  and set with a fixed timer value, and a data computing module PA 15  is electrically connected to the counter PA 13 . 
         [0007]    When doing the calibration by using the above mentioned technology, the touch pad PA 11  is untouched and the waveform generation module PA 12  generates the oscillating waves  100 ,  200 ,  300 . Concretely speaking, the above mentioned oscillating waves  100 ,  200 ,  300  are defined as being composed of an upward section and a downward section. That is, the section between time t 0  and t 2  in  FIG. 2  is the oscillating wave  100 , the section between time t 2  and t 4  is the oscillating wave  200 , and the section between time t 4  and t 6  is the oscillating wave  300 . During the calibration, the timer PA 14  measures the above mentioned fixed timer value (e.g. 1 ms) and triggers the counter PA 13  to count the number of the generated oscillating waves within the fixed timer value when the measured time equals to the fixed timer value. For example, as the fixed time value is the time period between time t 0  and t 4  in  FIG. 2  (i.e. t 4  minus t 0 ), then, the counter number would be two, i.e. oscillating waves  100  and  200 . Then, the computed data (such as the waveform showing the relationship between the counted number and time) would be transmitted to the data computing module PA 15  for computing a result with a better signal to noise ratio (SNR). 
         [0008]    However, in general, for the calibration method in which the timer PA 14  is set to measure a fixed time value, the data computing module PA 15  needs to conduct the switches (not shown) in the waveform generating module PA 12  repeatedly to choose the number of constant currents (not shown) for accessing a better signal to noise ratio. Because the calibration method needs to run the test repeatedly, it would spend lots of time and thus is not cost-efficient. 
         [0009]    In addition, when determining the existence of a touch, the applicable algorithm of the data computing module PA 15  is also restricted by the above mentioned calibration method. Because the determination is based on the number counted by the counter, a complicated method should be used. For example, the data computing module PA 15  in practice may use a filter with various filtering coefficients (e.g. eight different filtering coefficients) for computing the counted data from the counter PA 13 . Such determination would be quite time-consuming and thus there exists a need to improve the technology in present. 
       SUMMARY OF THE INVENTION 
       [0010]    As mentioned, the conventional art proceeding the calibration by setting the timer to measure a fixed time value has the problems of long calibration time and a time-consuming determination process for determining the existence of a touch. Accordingly, a touch calibration system and a method thereof is provided with the feature of having the counter set with a fixed count value to resolve the above mentioned problem. 
         [0011]    Based on the aforementioned object, a touch calibration system is provided in accordance with an embodiment of the present invention. The touch calibration system comprises a touch pad, a waveform generation module, a counter, a first timer, and a storage module. The waveform generation module is electrically connected to the touch pad for generating at least an oscillating wave. The counter is electrically connected to the waveform generation module and set with a fixed counter value, for counting an oscillation number of the oscillating wave generated by the waveform generation module under a calibration mode, and transmitting a count signal representing the oscillation number when the oscillation number reaches the fixed count value. The first timer is electrically connected to the timer, for measuring a calibrated oscillating time, and for receiving the count signal to transmitting a timer signal representing the calibrated oscillating time measured by the first timer. The storage module is electrically connected to the first timer, for receiving the timer signal to store the calibrated oscillating time to complete the calibration mode, wherein the calibration mode is defined as that the touch pad stops receiving a touch signal generated from a user. 
         [0012]    In accordance with an embodiment of the present invention, a touch calibration method is provided in the present invention. The touch calibration method is applicable to a touch calibration system, for calibrating the touch calibration system under a calibration mode. The touch calibration system includes a touch pad, a waveform generation module, a counter, a first timer, and a storage module, wherein the waveform generation module is electrically connected to the touch pad, the counter is electrically connected to the waveform generation module, the first timer is electrically connected to the counter, the storage module is electrically connected to the first timer. In the touch calibration method, the counter is firstly set with a fixed counter value. Then, at least an oscillating wave is generated by the waveform generation module. Afterward, an oscillation number of the oscillating wave generated by the waveform generation module is counted by the counter, and a calibrated oscillating time is measured by the first timer. Thereafter, a determination is carried out to determine whether the oscillation number reaches the fixed counter value. Finally, if the determination is yes, the calibrated oscillating time measured by the first timer is stored in the storage module. The calibration mode is defined as that the touch pad stops receiving a touch signal generated from a user. 
         [0013]    In accordance with a preferred embodiment of the touch calibration system and the method thereof of the present invention, the storage module is a second timer, the first timer is composed of a plurality of T-type flip-flops, the second timer is composed of a plurality of D-type flip-flops, and the waveform generation module is a relaxation oscillator circuit. 
         [0014]    By using the touch calibration system and the touch calibration method provided in the present invention, because a fixed counter value rather than a fixed time value is measured, the touch calibration process can be completed with only one calibration step and does not need to charge the constant current capacitor or the grounded capacitor repeatedly. Thus, the calibration time can be significantly reduced. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The present invention will now be specified with reference to its preferred embodiment illustrated in the drawings, in which: 
           [0016]      FIG. 1  is a block diagram of a conventional touch calibration system. 
           [0017]      FIG. 2  is a schematic view of an oscillating wave of the conventional touch calibration system. 
           [0018]      FIG. 3  is a block diagram of a touch calibration system in accordance with a preferred embodiment of the present invention. 
           [0019]      FIG. 4  is a circuit diagram of a waveform generation module in accordance with a preferred embodiment of the present invention; 
           [0020]      FIG. 5  is a circuit diagram of the first timer and the second timer in accordance with a preferred embodiment of the present invention; 
           [0021]      FIG. 6  is a flow chart showing a touch calibration method in accordance with a preferred embodiment of the present invention; 
           [0022]      FIG. 7  is a flow chart showing a touch determination method in accordance with a preferred embodiment of the present invention; and 
           [0023]      FIG. 8  is a schematic view of a count data waveform in accordance with a preferred embodiment of the present invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0024]    There are various embodiments of the touch calibration system and the touch calibration, which are not repeated hereby. Only one preferred embodiment is mentioned in the following paragraph as an example. 
         [0025]    Please refer to  FIG. 3  to  FIG. 5 , wherein  FIG. 3  is a block diagram of a touch calibration system in accordance with a preferred embodiment of the present invention,  FIG. 4  is a circuit diagram of a waveform generation module in accordance with a preferred embodiment of the present invention, and  FIG. 5  is a circuit diagram of the first timer and the second timer in accordance with a preferred embodiment of the present invention. 
         [0026]    As shown, the touch calibration system  1  includes a touch pad  11 , a waveform generation module  12 , a counter  13 , a first timer  14 , a storage module  15  and a data computing module  16 . The touch pad  11  is the device for the user to implement touch control. In general, the touch pad  11  includes capacitors. The waveform generation module  12 , such as the relaxation oscillator circuit, is electrically connected to the touch pad  11 . The relaxation oscillator circuit shown in  FIG. 4 , which is composed of SR flip-flops, comparators, resistors and capacitors, is merely an example of the present invention. The present invention is not so restricted. The layout as well as the type of oscillator circuit to be used may depend on the design in practice. 
         [0027]    The counter  13  is electrically connected to the waveform generation module  12  and can be composed of at least one T-type flip-flop. In addition, the counter  13  is set with a fixed counter value. The fixed counter value, such as ten-thousand, is preset at the beginning. In the present exemplary embodiment, a fixed counter value of two is used as an example for simplifying the description. 
         [0028]    The first timer  14  is electrically connected to the timer  13  and can be composed of a plurality of T-type flip-flops. In addition, the first timer  14  of the present embodiment is not set with a fixed time as described in the conventional art. The storage module  15  is electrically connected to the first timer  14  and can be a second timer. The second timer can be composed of a plurality of D-type flip-flops. However, the present invention is not so restricted. The data computing module  16  is electrically connected to the counter  13  and can be composed of at least one filter (not shown). 
         [0029]    In practice, as the touch calibration system  1  is operated under a calibration mode (in the present embodiment, the calibration mode is defined as that the touch pad stops receiving a touch signal generated from a user), the waveform generation module  12  will generate the oscillating waves  100 ,  200 ,  300  as shown in  FIG. 2 . Meanwhile, the counter  13  will count the oscillation numbers of the oscillating waves  100 ,  200 ,  300  generated by the waveform generation module  12 . Because the fixed count value is two, the counter  13  will transmit a count signal S 1  representing the oscillation number as the oscillating wave  200  generated by the waveform generation module  12  is counted (i.e. two oscillating waves  100 ,  200  has been generated and the fixed count value is reached). At the same time, the first timer  14  will measure a calibrated oscillating time and transmit a timer signal S 2  representing the calibrated oscillating time measured by the first timer  14  when receiving the count signal S 1 . For example, as the fixed count value is two, the first timer  14  stops measuring at time t 4  (as shown in  FIG. 2 ) and thus the calibrated oscillating time would be the period between time t 4  and to. The first timer  14  will transmit the timer signal S 2  to the storage module  15  to have the storage module  15  store the calibrated oscillating time as a parameter for actually determining whether there exists a touch and the calibration mode is completed. 
         [0030]      FIG. 6  is a flow chart showing a touch calibration method in accordance with a preferred embodiment of the present invention. As shown, the touch calibration method is applicable to the touch calibration system  1  as shown in  FIG. 3  and proceeds the following steps under a calibration mode (the calibration mode is also defined as that the touch pad  11  stops receiving a touch signal generated from a user): 
         [0031]    Step S 101 : setting the counter  13  with a fixed counter value. 
         [0032]    Step S 102 : generating, by the waveform generation module  12 , at least an oscillating wave. 
         [0033]    Step S 103 : counting, by the counter  13 , an oscillation number of the oscillating wave generated by the waveform generation module  12  and measuring, by the first timer  14 , a calibrated oscillating time. 
         [0034]    Step S 104 : determining whether the oscillation number reaches the fixed counter value. 
         [0035]    Step S 105 : storing, in the storage module  15 , the calibrated oscillating time measured by the first timer  14 . 
         [0036]    The content of steps S 101  to S 105  are identical to the aforementioned description of the touch calibration system  1  and thus is not repeated here. 
         [0037]    Please refer to  FIG. 7  and  FIG. 8 , wherein  FIG. 7  is a flow chart showing a touch determination method in accordance with a preferred embodiment of the present invention and  FIG. 8  is a schematic view of a count data waveform in accordance with a preferred embodiment of the present invention. As shown, after storing the calibrated oscillating time in the storage module  15  to complete the calibration, the aforementioned touch calibration system can be used in the actual touch circuit for determining whether the user touch the touch pad  11 . The method for determining whether there exists a touch comprises the following steps: 
         [0038]    Step S 201 : accessing, by the first timer  14 , the calibrated oscillating time from the storage module  15 . 
         [0039]    Step S 202 : measuring, by the first timer  14 , a touch determination time, and counting, by the counter  13 , at least one oscillating wave. 
         [0040]    Step S 203 : determining whether the touch determination time reaches the calibrated oscillating time. 
         [0041]    Step S 204 : transmitting, by the counter  13 , a count data. 
         [0042]    Step S 205 : filtering, by at least one filter, noise in the count data to generate a filtered count data. 
         [0043]    Step S 206 : determining whether the touch pad  11  is touch controlled by the user by using the filtered count data and the fixed count value. 
         [0044]    Because the first timer  14  is composed of a plurality of T-type flip-flops, in step S 201 , the reset/set (RS) output can be read as the calibrated oscillating time stored in the storage module  15  of the second timer. In step S 202 , as the waveform generation module  12  generating the oscillating wave (not shown), the first timer  14  begins measuring the touch determination time and the counter  13  counting the at least one oscillating wave synchronously. In step S 203 , as it is determined that the touch determination time reaches the calibrated oscillating time, step S 204  would be carried out and the counter  13  would transmit a count data waveform  400  as shown in  FIG. 8 , i.e. a waveform of number versus time. Because in practice, the waveform would be mixed with some noise, Step S 205  is then carried out by using at least one filter in the data computing module  16  to remove the noise in the count data so as to generate a filtered count data (not shown). Two filters is preferred in the present embodiment, however, the present invention is not so restricted. The number of filters would be decided by the need in practice. 
         [0045]    Finally, the determination step S 206  is carried out. An exemplary method for the determination step is mentioned below. As the calibrated oscillating time is t 4 , the number corresponding to t 4  can be estimated. As the number is one and the fixed count value is two, the fixed count value is greater than the number corresponding to t 4  and thus it is preliminarily determined that the touch pad  11  is touch controlled. It should be noted that the above mentioned method is a simplified method, in practice, the fixed count value might be a large number, such as ten-thousand (denoted as f 1 ) for example, and the counted number (denoted as f 2 ) is also a large number, then, the determination step may be carried out by comparing  12  with f 1  subtracted by 6% of f 1 , i.e. by using the function: f 2 &lt;f 1 *94%, to determine whether there is a touch. However, the present invention is not so restricted. 
         [0046]    It is noted that, because the fixed count value is used in the present invention, the comparator of the waveform generation module  12  does not need a reference voltage and a constant current with precise value (i.e. the value, such as the level of the reference voltage or the number of constant currents, does not need to be calibrated for the specific purpose). Thus, in compared with the conventional technology shown in  FIG. 1 , the present invention does not need to choose the number of constant currents for accessing a better signal to noise ratio such that the calibration cost can be effectively reduced. 
         [0047]    In conclusion, by using the touch calibration system and the calibration method of the present invention, because a fixed counter value is measured, the touch calibration process can be completed with only one calibration step without the need of charging the constant current capacitor or the grounded capacitor repeatedly. In the present invention and thus the time consumption can be reduced to enhance convenience in practice. 
         [0048]    The detail description of the aforementioned preferred embodiments is for clarifying the feature and the spirit of the present invention. The present invention should not be limited by any of the exemplary embodiments described herein, but should be defined only in accordance with the following claims and their equivalents. Specifically, those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiments as a basis for designing or modifying other structures for carrying out the same purposes of the present invention without departing from the scope of the invention as defined by the appended claims.