Abstract:
The present invention relates to a touch gesture identification method for a surface capacitive touch screen, so as to identify touch gestures executed by at least two touching objects to the surface capacitive touch screen having a transparent substrate, an electrode layer and a transparent protection layer. The surface capacitive touch screen has advantages of simple framework, easy to be manufactured and low cost, so that this surface capacitive touch screen is widely applied in electronic and electrical products with different screen sizes. The main feature of the method is that the displaying images on the touch screen can be zoom in or zoom out by way of computing the difference between a first-time sensed current and a second-time sensed current resulted from the touch gestures executed by the two touching objects and detected by the surface capacitive touch screen.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Technical Field 
         [0002]    The present invention relates to a touch gesture identification method for touch screens, and more particularly to a touch gesture identification method capable of being applied in surface capacitive touch screens with various screen sizes for detecting and identifying a touch gesture made by two touching objects. 
         [0003]    2. Description of Related Art 
         [0004]    With the progress of science and technology, 3C products, such as mobile phones, tablet PCs or notebooks, now include touch screens instead of traditional liquid crystal display (LCD) screens. 
         [0005]    By technology principles, the touch screens are divided into resistive touch screen, capacitive touch screen, infrared-ray touch screen, surface acoustic wave touch screen, electromagnetic touch screen, and optical touch screen; in which, the capacitive touch screen is widely used in various electronic products because of having the advantages of high transmittance, flexible touch and long service life. Please refer to  FIG. 1 , there is shown an exploded view of a conventional capacitive touch screen. As shown in  FIG. 1 , the conventional capacitive touch screen  10 ′ includes: a transparent substrate  11 ′, an electrode layer  13 ′ and a protection layer  14 ′, wherein the electrode layer  13 ′ includes a transparent conductive layer  130 ′, and two opposite X electrodes  131 ′ and Y electrodes  132 ′ are formed around the side edges of the transparent conductive layer  130 ′. 
         [0006]    Please simultaneously refer to  FIG. 2 , which illustrates a schematic signal receiving diagram of the conventional capacitive touch screen. As shown in  FIG. 2 , four conducting wires  151 ,  152 ,  153 , and  154  are connected to four corners of the capacitive touch screen  10 ′, used to receive four AC signal AC 1 ′, AC 2 ′, AC 3 ′, and AC 4 ′ for detecting and computing a touch point P′ on the capacitive touch screen  10 ′. When the capacitive touch screen  10 ′ is operated, the AC signal (AC 1 ′, AC 2 ′, AC 3 ′, and AC 4 ′) is a voltage signal with square wave or sine wave, and the four conducting wires ( 151 ′,  152 ′,  153 ′, and  154 ′) conduct currents I 1 ′, I 2 ′, I 3 ′, and I 4 ′, respectively. Therefore, touch point P′ can be computed by measuring current differences ΔI 1 ′, ΔI 2 ′, ΔI 3 ′, and ΔI 4 ′ of the conducting wires ( 151 ′,  152 ′,  153 ′, and  154 ′), wherein the touch point P′ is computed by following formula: 
         [0000]        X =(Δ I 3 +ΔI 4− ΔI 1−Δ I 2)/(Δ I 1 +ΔI 2 +ΔI 3 +ΔI 4)
 
         [0000]        Y =(Δ I 1 +ΔI 4− ΔI 3− ΔI 2)/(Δ I 1 +ΔI 2 +ΔI 3 +ΔI 4)
 
         [0007]    The technology framework of the above-mentioned capacitive touch screen  10 ′ is very simple, so that the capacitive touch screen  10 ′ has the advantages of low cost and easy to be produced. However, this capacitive touch screen  10 ′ cannot provide multi touch (MT) function, and that is the main drawback of the capacitive touch screen  10 ′. When two touch points are made on the capacitive touch screen  10 ′ for carrying out a touch gesture, for example, zoom-in gesture or zoom-out gesture, the currents conducted by the conducting wires may counteract to each other due to the positions of the two touch points are opposite, so that the touch points cannot and the touch gesture cannot be determined. For above reason, it can easily know that the capacitive touch screen  10 ′ is not an ideal touch technology. 
         [0008]    Accordingly, in view of the surface capacitive touch screen  10 ′ is not an ideal touch technology, the touch manufacturers propose a projected capacitive touch screen in order to solve the drawback of the surface capacitive touch screen  10 ′. Please refer to  FIG. 3 , there is shown an exploded view of a projected capacitive touch screen. As shown in  FIG. 3 , the projected capacitive touch screen  20 ′ includes: a Y electrode layer  24 ′, a transparent dielectric layer  23 ′, an X electrode layer  22 ′, and a transparent substrate  21 ′, wherein a plurality of sensing elements  25 ′ are formed the Y electrode layer  24 ′ and the X electrode layer  22 ′ by rows and columns. These sensing elements  25 ′ are respectively connected with a plurality of conducting wires  28 ′, and used for sensing at least one touch point on the projected capacitive touch screen  20 ′. 
         [0009]    Comparing to the surface capacitive touch screen  10 ′, this projected capacitive touch screen  20 ′ includes multi layers for constituting a sensing matrix pattern; therefore, the multitouch (MT) operation can be achieve when the projected capacitive touch screen  20 ′ is operated. However, since the projected capacitive touch screen  20 ′ uses the sensing matrix (including multi-column sensing and multi-row sensing) to detecting the touch points, the sensing matrix technology is still an advanced technology, such that the projected capacitive touch screen  20 ′ has the disadvantages of cannot be easily manufactured and high cost. 
         [0010]    According to above descriptions, it is able to know that the projected capacitive touch screen  20 ′ can not be widely applied because of high cost and complex manufacturing. For this reason, the projected capacitive touch screen  20 ′ is merely applied on the electronic products with small screen size, such as smart phones and tablet PCs. On the contrary, because the projected capacitive touch screen  20 ′ has the disadvantages of cannot be easily manufactured and high cost, the projected capacitive touch screen  20 ′ can not be applied the electronic products with large screen size, for example, notebooks, industrial PCs, POS systems, ATMs, medical devices, monitors, game consoles, game machines, etc. 
         [0011]    Thus, to make the surface capacitive touch screen simultaneously include the functions of “multitouch” and “touch gesture sensing” and capable of being applied on the electronics devices with different screen sizes becomes the most important issue. And accordingly, in view of the shortcoming of the conventional stylus, the inventor of the present application has made great efforts to make inventive research thereon and eventually provided a touch Gesture identification method for surface capacitive touch screen. 
       BRIEF SUMMARY OF THE INVENTION 
       [0012]    The primary objective of the present invention is to provide a touch Gesture identification method for surface capacitive touch screen, which can be used for identifying a touch gesture made by at least two touching objects to a surface capacitive touch screen, and then zooming in or zooming out the displaying images on the screen by way of computing the difference between a first-time sensed current and a second-time sensed current resulted from the touch gesture; This method includes the advantages of simple framework, easy to be manufactured and low cost and can be widely applied in the surface capacitive touch screens with various screen sizes. 
         [0013]    Accordingly, for achieving the above objective of the present invention, the inventors propose a touch Gesture identification method for surface capacitive touch screen, which is used for identifying a touch gesture made by at least two touching objects to a surface capacitive touch screen having a transparent substrate, an electrode layer and a transparent protection layer, and comprises the steps of: 
         [0000]    (1) at least two touching objects touching the transparent protection layer of the surface capacitive touch screen at a first time;
 
(2) a first conducting wire, a second conducting wire, a third conducting wire, and a fourth conducting wire of a transparent conductive layer of the electrode layer producing a first-time first current, a first-time second current, a first-time third current, and a first-time fourth current, respectively;
 
(3) computing the summation of the first-time first current and the first-time third current, and the summation of the first-time second current and the first-time fourth current;
 
(4) the touching objects touching the transparent protection layer of the surface capacitive touch screen at a second time;
 
(5) the first conducting wire, the second conducting wire, the third conducting wire, and the fourth conducting wire of the transparent conductive layer of the electrode layer producing a second-time first current, a second-time second current, a second-time third current, and a second-time fourth current, respectively;
 
(6) computing the summation of the second-time first current and the second-time third current, and the summation of the second-time second current and the second-time fourth current;
 
(7) determining whether the summation of the second-time first current and the second-time third current is greater than the summation of the first-time first current and the first-time third current, or the summation of the second-time second current and the second-time fourth current is greater than the summation of the first-time second current and the first-time fourth current, if yes, going to step (8); otherwise, going to step (9);
 
(8) zooming in the displaying images on the surface capacitive touch screen, and ending the steps; and
 
(9) zooming out the displaying images on the surface capacitive touch screen, and ending the steps.
 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0014]    The invention as well as a preferred mode of use and advantages thereof will be best understood by referring to the following detailed description of an illustrative embodiment in conjunction with the accompanying drawings, wherein: 
           [0015]      FIG. 1  is an exploded view of a conventional capacitive touch screen; 
           [0016]      FIG. 2  is a schematic signal receiving diagram of the conventional capacitive touch screen; 
           [0017]      FIG. 3  is an exploded view of a projected capacitive touch screen; 
           [0018]      FIG. 4  is an exploded view of a surface capacitive touch screen according to the present invention; 
           [0019]      FIG. 5  is a schematic signal receiving diagram of the surface capacitive touch screen according to the present invention; and 
           [0020]      FIG. 6A  and  FIG. 6B  are flow charts of a touch gesture identification method for the surface capacitive touch screen according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0021]    To more clearly describe a touch gesture identification method for a surface capacitive touch screen according to the present invention, embodiments of the present invention will be described in detail with reference to the attached drawings hereinafter: 
         [0022]    Before describing the touch gesture identification method for the surface capacitive touch screen of the present invention, the structure of the surface capacitive touch screen must be introduced firstly. Please refer to  FIG. 4  and  FIG. 5 , which illustrate an exploded view and a schematic signal receiving diagram of the surface capacitive touch screen. As shown in  FIG. 4  and  FIG. 5 , the surface capacitive touch screen includes: a transparent substrate  11 , an electrode layer  12  and a transparent protection layer  13 , wherein the material of the transparent substrate  11  can be glass, polymethylmethacrylate (PMMA) or polyethylene terephthalate (PET). The transparent protection layer  13  is used for covering and protecting the electrode layer  12  and the material thereof can be SiO 2 , glass, PMMA, or PET. 
         [0023]    The electrode layer  12  is disposed on the transparent substrate  11  and includes a transparent conductive layer  120 . The material of the transparent conductive layer  120  can be Indium-Tin-Oxide (ITO) or carbon nanotube (CNT), and the side edges of the transparent conductive layer  120  are formed with a first X electrode  121 , a second X electrode  121   a,  a first Y electrode  122 , and a second Y electrode  122   a,  respectively; in which two ends of the first X electrode  121  are connected to the first Y electrode  122  and the second Y electrode  122   a;  And the second X electrode  121   a  is opposite to the first X electrode  121  and connected to the first Y electrode  122  and the second Y electrode  122   a  by two ends thereof 
         [0024]    Inheriting to above descriptions, moreover, the connecting end of the first X electrode  121  and the first Y electrode  122  is coupled with a first conducting wire  151 , the connecting end of the first Y electrode  122  and the second X electrode  121   a  is coupled with a second conducting wire  152 , the connecting end of the second X electrode  121   a  and the second Y electrode  122   a  is coupled with the third conducting wire  153 , and the connecting end of the second Y electrode  122   a  and the first X electrode  121  is coupled with the fourth conducting wire  154 . As shown in  FIG. 5 , a first current I 1 , a second current I 2 , a third current I 3 , and a fourth current I 4  flow through the first conducting wire  151 , the second conducting wire  152 , the third conducting wire  153 , and the fourth conducting wire  154 , respectively. 
         [0025]    After introducing the structure of the surface capacitive touch screen  1 , the touch gesture identification method for the surface capacitive touch screen proposed in the present invention will be next introduced and detailed described in follows. Please refer to  FIG. 4  and  FIG. 5  again, and simultaneously referring to  FIG. 6A  and  FIG. 6B , there are shown flow charts of the touch gesture identification method for the surface capacitive touch screen. 
         [0026]    The flow of the touch gesture identification method is firstly preceded to step (S 01 ) and step (S 02 ), two touching objects OT touch the transparent protection layer  13  of the surface capacitive touch screen  1  at a first time, and then the first conducting wire  151 , the second conducting wire  152 , the third conducting wire  153 , and the fourth conducting wire  154  of the transparent conductive layer  120  of the electrode layer  12  produce a first-time first current I 11 , a first-time second current I 21 , a first-time third current I 31 , and a first-time fourth current I 41 , respectively. Next, the method flow is proceeded to step (S 03 ), a back-end processor (not shown) computes the summation of the first-time first current I 11  and the first-time third current I 31  as well as the summation of the first-time second current I 21  and the first-time fourth current I 41 . 
         [0027]    After that the flow is proceeded to step (S 04 ) and step (S 05 ), the touching objects OT touch the transparent protection layer  13  of the surface capacitive touch screen  1  at a second time, and then the first conducting wire  151 , the second conducting wire  152 , the third conducting wire  153 , and the fourth conducting wire  154  of the transparent conductive layer  120  of the electrode layer  12  produce a second-time first current I 12 , a second-time second current I 22 , a second-time third current I 32 , and a second-time fourth current I 42 , respectively. Next, the flow is proceeded to step (S 06 ), the back-end processor computes the summation of the second-time first current I 12  and the second-time third current I 32 , and the summation of the second-time second current I 22  and the second-time fourth current I 42 . Sequentially, in step (S 07 ), it determines whether the summation of the second-time first current I 12  and the second-time third current I 32  is greater than the summation of the first-time first current I 11  and the first-time third current I 31  (i.e., if (I 12 + I   32 ) &gt; ( I   11 +I 31 ) ?), or the summation of the second-time second current I 22  and the second-time fourth current I 42  is greater than the summation of the first-time second current I 21  and the first-time fourth current I 41  (i.e., if (I 12 +I 32 )&gt;(I 11 +I 31 )?). In the step (S 07 ), when (I 12 +I 32 ) &gt; (I 11 +I 31 ), it means that the touch gesture is a “zooming-in gesture”, and then step ( 8 ) would be processed for zooming in the displaying images on the surface capacitive touch screen  1 . On the contrary, when (I 12  +I 32 )&gt;(I 11  I 31 ), it means that the touch gesture is a “zooming- out gesture”, and then step (9) would be processed for zooming out the displaying images on the surface capacitive touch screen  1 . 
         [0028]    Moreover, as sown in  FIG. 4 , when the touching objects touch a touching point P on the transparent protection layer  13  of the surface capacitive touch screen  1  at the first time, the electrode layer  120  would produce a first current difference ΔI 1 , a second current difference ΔI 2 , a third current difference ΔI 3 , and a fourth current difference ΔI 4 , therefore the back-end processor can computes the X-axis coordinate position and the Y-axis coordinate position according to following formula: 
         [0000]      X-axis coordinate position=[(ΔI3 +ΔI 4)−ΔI1 −ΔI 1 −ΔI 2 ]/[ΔI 1 +ΔI 2 +ΔI 3 +ΔI 4]
 
         [0000]    and 
         [0000]      Y-axis coordinate position=[(Δ I 1 +ΔI 4)−Δ I 3 −ΔI 2 ]/[ΔI 1 +ΔI 2 +ΔI 3 +ΔI 4],
 
         [0000]    wherein the first current differenceΔI 1  is obtained by subtracting the first-time first current from the second-time first current I 12 , the second current difference ΔI 2  is obtained by subtracting the first-time second current I 21  from the second-time second current I 12 , the third current difference ΔI 3  is obtained by subtracting the first-time third current I 31  from the second-time third current I 22 , and the fourth current difference ΔI 4  is obtained by subtracting the first-time fourth current I 41  from the second-time fourth current I 42 . 
         [0029]    Thus, above descriptions have been completely and clearly disclosed the touch gesture identification method for surface capacitive touch screen proposed by the present invention, and in summary, the present invention has the following advantages: 
         [0000]    1. The surface capacitive touch screen is made of a transparent substrate, an electrode layer and a transparent protection layer, therefore, the surface capacitive touch screen has advantages of simple framework, easy to be manufactured and low cost.
 
2. The touch Gesture identification method of the present invention can be used for identifying a touch gesture made by at least two touching objects to a surface capacitive touch screen, and then zooming in or zooming out the displaying images on the screen by way of computing the difference between a first-time sensed current and a second-time sensed current resulted from the touch gesture.
 
3. Inheriting to above point 1 and pint 2, because this touch Gesture identification method and the surface capacitive touch screen have the advantages of simple framework, easy to be manufactured and low cost and can be widely applied in the surface capacitive touch screens with various screen sizes; for example, smart phones, tablet PCs, notebooks, industrial PCs, POS systems, ATMs, medical devices, monitors, game consoles, game machines, etc.
 
         [0030]    The above description is made on embodiments of the present invention. However, the embodiments are not intended to limit scope of the present invention, and all equivalent implementations or alterations within the spirit of the present invention still fall within the scope of the present invention.