Abstract:
The present invention provides a touch pad operable with multi-objects and a method of operating such a touch pad. The touch pad includes a touch structure for sensing touch points of a first and a second object and a controller for generating corresponding touching signals and related position coordinates. Moreover, the controller calculates at least two movement amount indexes according to coordinate differences between these position coordinates, thereby generating a movement amount control signal to control behaviors of a software object.

Description:
CROSS REFERENCE 
     This is a continuation-in-part application of the U.S. patent application Ser. No. 13/345,726, filed on Jan. 8, 2012, which is a divisional application of the U.S. patent application Ser. No. 12/057,883, filed on Mar. 28, 2008, the contents of which are herein incorporated by reference in their entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a touch pad, and more particularly to a touch pad operable with multi-objects. The present invention also relates to a method of operating such a touch pad. 
     BACKGROUND OF THE INVENTION 
     Nowadays, consumable electronic products with touch pads or touch panels are becoming increasingly popular because of their ease and versatility of operation. A representative electronic product with a touch panel is for example an iPhone, which is a mobile phone designed and marketed by Apple Inc. For helping the user well operate the electronic products, the touch sensing interfaces of the electronic products are developed in views of humanization and user-friendliness. 
     Conventionally, by simply touching the surface of the touch sensing interface with a finger, the user can make selections and move a cursor. Nowadays, with increasing demand of using the touch sensing interface as a control unit, operating the touch pads or touch panels with only one finger is not satisfied. As a consequence, touch sensing interfaces operated with two fingers have been developed. Take the iPhone for example. It is possible to zoom in and out of web pages or photos by placing two fingers on the touch sensing interface and spreading them farther apart or closer together, as if stretching or squeezing the image. The iPhone interface, however, enables the user to move the content up/down or leftward/rightward or rotate the content by a touch-drag motion of a single finger. 
     Although the iPhone interface makes it easy to zoom in or out of images by spreading two fingers farther apart or closer together, there are still some drawbacks. For example, since the software for reading out the user&#39;s gestures is based on complicated moving control means, there is a need of providing a simplified method for quickly reading out the user&#39;s gestures. In the present invention, capacitive or resistive touch pads are concerned. 
     Moreover, since the software object is moved up/down or leftward/rightward or rotated by moving a single finger on the touch sensing interface, it is necessary to rotate the software object at a specified angle or move the software object along multi-directions with two fingers. Therefore, there is also a need of rotating the software object at a specified angle or moving the software object along multi-directions with two fingers. 
     U.S. Pat. No. 7,138,983 discloses a method and an apparatus for detecting and interpreting path of designated positions. The U.S. patent determines whether an object should be rotated in clockwise or anticlockwise directions based on the measured angle difference value. If the measured angle difference value is negative as shown by the example on  FIGS. 63A to 63D  of that U.S. patent, the user&#39;s gesture is interpreted as a clockwise rotation operation. If the measured angle difference value is positive as shown by the example on  FIGS. 65A to 65D , the user&#39;s gesture is interpreted as an anticlockwise rotation operation. 
     However, merely relying on the measured angle difference, the foregoing method may misinterpret some gestures. With reference to  FIG. 13 , if the user has no intention to perform a clockwise rotation operation but unintentionally contacts the touch panel at position C, the appearance of the touch point C will be interpret as the clockwise rotation operation because the measured angle difference is a negative value, i.e. (∠C-∠B)&lt;0. 
     SUMMARY OF THE INVENTION 
     The present invention provides a method of operating a touch pad with at least two fingers to move the software object up/down or leftward/rightward, rotate the software object at a specified angle, and zoom in/out of the software object. 
     The present invention further provides a touch pad operable with at least two fingers to move the software object up/down or leftward/rightward, rotate the software object at a specified angle, and zoom in/out of the software object. 
     In accordance with an aspect of the present invention, there is provided a method of operating a touch pad with multi-objects. First of all, touch points of first and second objects on the touch pad are sensed to assert a first position coordinate (X 1 , Y 1 ) and a second position coordinate (X 2 , Y 2 ), respectively. Then, the second object is moved on the touch pad to a further touch point, and the further touch point is sensed to assert a third position coordinate (X 3 , Y 3 ). According to coordinate differences between the first, second and third position coordinates, at least two movement amount indexes are calculated, wherein a first movement amount index is obtained according to a coordinate difference between the first and second position coordinates. Afterwards, a movement amount control signal is generated according to the at least two movement amount indexes. 
     In an embodiment, the first object is a first finger, the second object is a second finger, and the first, second and third position coordinates are obtained in an absolute two-dimensional coordinate system or a relative two-dimensional coordinate system. 
     In an embodiment, the method further includes the following steps. A first angle of the line through the first position coordinate and the second position coordinate with respect to the x-axis is measured and defined as the first movement amount index. Then, a second angle of the line through the first position coordinate and the third position coordinate with respect to the x-axis, is measured and defined as a second movement amount index. Then, an angle difference between the first angle and the second angle is calculated. According to the positive or negative sign of the angle difference, the movement amount control signal is generated to control behaviors of a software object. For example, the software object is a volume control key and the behaviors of the software object include displacement amount and displacement direction of the volume control key. Alternatively, the software object is a digital image and the behaviors of the software object include rotational amount and rotational direction of the digital image. 
     In an embodiment, the method further includes the following steps. A first slope S 112  of the line through the first position coordinate and the second position coordinate is measured as the first movement amount index. A second slope S 113  of the line through the first position coordinate and the third position coordinate is measured as a second movement amount index. A third slope S 123  of the line through the second position coordinate and the third position coordinate is measured as a third movement amount index. If S 112 ≧0, S 113 ≧0, S 123 &lt;0, (Y 2 −Y 3 )&gt;0 and (X 2 −X 3 )&lt;0, or if S 112 ≦0, S 113 ≦0, S 123 &gt;0, (Y 2 −Y 3 )&lt;0 and (X 2 −X 3 )&lt;0, the movement amount control signal is generated to control a first rotational action of the software object. Whereas, if S 112 ≧0, S 113 ≧0, S 123 &lt;0, (Y 2 −Y 3 )&lt;0 and (X 2 −X 3 )&gt;0, or if S 112 ≦0, S 113 ≦0, S 123 &gt;0, (Y 2 −Y 3 )&gt;0 and (X 2 −X 3 )&gt;0, the movement amount control signal is generated to control a second rotational action of the software object. For example, the first rotational action and the second rotational action are respectively a clockwise rotational action and a counterclockwise rotational action. The software object is a volume control key and the behaviors of the software object include displacement amount and displacement direction of the volume control key. Alternatively, the software object is a digital image and the behaviors of the software object include rotational amount and rotational direction of the digital image. 
     In an embodiment, the method further includes the following steps. A first slope S 212  of the line through the first position coordinate and the second position coordinate is measured as the first movement amount index. A second slope S 213  of the line through the first position coordinate and the third position coordinate is measured as a second movement amount index. A third slope S 223  of the line through the second position coordinate and the third position coordinate is measured as a third movement amount index. If S 212 ≧0, S 213 ≧0, S 232 ≧0, (X 2 −X 1 )&gt;(X 3 −X 1 ), and (Y 2 −Y 1 )&gt;(Y 3 −Y 1 ), or if S 212 &lt;0, S 213 &lt;0, S 232 &lt;0, (X 2 −X 1 )&gt;(X 3 −X 1 ), and (Y 2 −Y 1 )&gt;(Y 3 −Y 1 ), the movement amount control signal is generated to control a first zoom in/out action of the software object. Whereas, if S 212 ≧0, S 213 ≧0, S 232 ≧0, (X 2 −X 1 )&lt;(X 3 −X 1 ), and (Y 2 −Y 1 )&lt;(Y 3 −Y 1 ), or if S 212 &lt;0, S 213 &lt;0, S 232 &lt;0, (X 2 −X 1 )&lt;(X 3 −X 1 ), and (Y 2 −Y 1 )&lt;(Y 3 −Y 1 ), the movement amount control signal is generated to control a second zoom in/out action of the software object. For example, the first zoom in/out action and the second zoom in/out action are respectively a zoom out action and a zoom in action. The software object is a digital image, and the behaviors of the software object include zoom in/out amount and zoom in/out direction of the digital image. 
     In an embodiment, the method further includes the following steps. The first object is moved on the touch pad to a further touch point, and the further touch point is sensed to assert a fourth position coordinate (X 4 , Y 4 ). Then, a third movement amount index is obtained according to a coordinate difference between the second and third position coordinates, a fourth movement amount index is obtained according to a coordinate difference between the first and fourth position coordinates, and a fifth movement amount index is obtained according to a coordinate difference between the fourth and third position coordinates. Afterwards, the movement amount control signal is generated according to the first, third, fourth and fifth movement amount indexes. 
     In an embodiment, the method further includes the following steps. A first slope S 312  of the line through the first position coordinate and the second position coordinate is measured as the first movement amount index. A third slope S 332  of the line through the second position coordinate and the third position coordinate is measured as a third movement amount index. A fourth slope S 314  of the line through the first position coordinate and the fourth position coordinate is measured as a fourth movement amount index. A fifth slope S 343  of the line through the fourth position coordinate and the third position coordinate is measured as a fifth movement amount index. If S 312 ≧0, S 332 ≧0, S 314 ≧0, S 343 ≧0, (X 2 −X 1 )&gt;(X 3 −X 4 ), and (Y 2 −Y 1 )&gt;(Y 3 −Y 4 ), or if S 312 &lt;0, S 332 &lt;0, S 314 &lt;0, S 343 &lt;0, (X 2 −X 1 )&gt;(X 3 −X 4 ), and (Y 2 −Y 1 )&gt;(Y 3 −Y 4 ), the movement amount control signal is generated to control a first zoom in/out action of the software object. Whereas, if S 312 ≧0, S 332 ≧0, S 314 ≧0, S 343 ≧0, (X 2 −X 1 )&lt;(X 3 −X 4 ), and (Y 2 −Y 1 )&lt;(Y 3 −Y 4 ), or if S 312 &lt;0, S 332 &lt;0, S 314 &lt;0, S 343 &lt;0, (X 2 −X 1 )&lt;(X 3 −X 4 ), and (Y 2 −Y 1 )&lt;(Y 3 −Y 4 ), the movement amount control signal is generated to control a second zoom in/out action of the software object. For example, the first zoom in/out action and the second zoom in/out action are respectively a zoom out action and a zoom in action. The software object is a digital image, and the behaviors of the software object include zoom in/out amount and zoom in/out direction of the digital image. 
     In accordance with another aspect of the present invention, there is provided a touch pad operable with multi-objects. The touch pad is communicated with a host and a display body, and includes a touch structure and a controller. The touch structure has a lower surface communicated with the display body and an upper surface for sensing touch points. When touch points of first and second objects on the touch pad are sensed, first and second touching signals are respectively generated. When the second object is moved on the touch pad to a further touch point and the further touch point is sensed, a third touching signal is generated. The controller is electrically connected to the touch structure and the host for receiving the first, second and third touching signals and generating a first position coordinate (X 1 , Y 1 ), a second position coordinate (X 2 , Y 2 ) and a third position coordinate (X 3 , Y 3 ), respectively. The controller calculates at least two movement amount indexes according to coordinate differences between the first, second and third position coordinates, thereby generating a movement amount control signal. A first movement amount index is obtained according to a coordinate difference between the first and second position coordinates. 
     The above objects and advantages of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a flowchart illustrating a method of operating a touch pad according to a first preferred embodiment of the present invention; 
         FIGS. 2A˜2D  are schematic two-dimensional coordinate diagrams illustrating the operating principles of the first preferred embodiment; 
         FIGS. 3A and 3B  are schematic diagrams illustrating an implementation example of controlling displacement amount and displacement direction of a volume control key according to the angle difference; 
         FIGS. 4A and 4B  are schematic diagrams illustrating another implementation example of controlling rotational amount and rotational direction of an image according to the angle difference; 
         FIG. 5  is schematic block diagram illustrating an interpreting system of the touch pad according to the present invention; 
         FIG. 6  is a flowchart illustrating a method of operating a touch pad according to a second preferred embodiment of the present invention; 
         FIG. 7  is a schematic two-dimensional coordinate diagram illustrating operating principles of the second preferred embodiment; 
         FIG. 8  is a flowchart illustrating a method of operating a touch pad according to a third preferred embodiment of the present invention; 
         FIG. 9  is a schematic two-dimensional coordinate diagram illustrating the operating principles of the third preferred embodiment; 
         FIGS. 10A and 10B  are schematic diagrams illustrating another implementation example of controlling zoom in/out amount and zoom in/out direction of the digital image. 
         FIG. 11  is a flowchart illustrating a method of operating a touch pad according to a fourth preferred embodiment of the present invention; 
         FIG. 12  is a schematic two-dimensional coordinate diagram illustrating the operating principles of the fourth preferred embodiment; and 
         FIG. 13  is a schematic diagram illustrating a gesture incorrectly interpreted as clockwise rotation operation using the conventional method of U.S. Pat. No. 7,138,983. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this invention are presented herein for purpose of illustration and description only. It is not intended to be exhaustive or to be limited to the precise form disclosed. 
     Hereinafter, an embodiment of operating a touch pad according to a first preferred embodiment of the present invention will be illustrated with reference to the flowchart of  FIG. 1  and the two-dimensional coordinate diagrams of  FIGS. 2A˜2D . 
     When a first object (e.g. a first finger F 1 ) is placed on a touch position of the touch pad  10  (Step A 1 ), the coordinate of the touch point is detected so as to assert a first position coordinate (X 1 , Y 1 ), as is shown in  FIG. 2A  and Step A 2  of  FIG. 1 . 
     Next, as shown in  FIG. 2B  and Step A 3  of  FIG. 1 , when a second object (e.g. a second finger F 2 ) is placed on another touch point of the touch pad  10 , the coordinate of the touch point is detected so as to assert a second position coordinate (X 2 , Y 2 ). With the first position coordinate serving as a reference point, a first movement amount index indicating a relation between the first position coordinate (X 1 , Y 1 ) and the second position coordinate (X 2 , Y 2 ) is measured. In this embodiment, the first movement amount index is for example a first angle θ 1 , i.e. θ 1 =arctan (Y 2 −Y 1 )/(X 2 −X 1 ). 
     Next, as shown in  FIG. 2C  and Step A 4  of  FIG. 1 , when the second finger F 2  is moved to and stayed at a further touch point of the touch pad  10 , the coordinate of the touch point is detected so as to assert a third position coordinate (X 3 , Y 3 ). In this embodiment, the second finger F 2  is moved from the initial position (i.e. the second position coordinate (X 2 , Y 2 )) to a destination position (i.e. the third position coordinate (X 3 , Y 3 )) in a clockwise direction M 11 . With the first position coordinate serving as a reference point, a second movement amount index indicating a relation between the first position coordinate (X 1 , Y 1 ) and the third position coordinate (X 3 , Y 3 ) is measured. In this embodiment, the second movement amount index is for example a second angle θ 2 , i.e. θ 2 =arctan (Y 3 −Y 1 )/(X 3 −X 1 ). 
     As shown in  FIG. 2D  and Step A 5  of  FIG. 1 , an angle difference θ between the first angle θ 1  and the second angle θ 2  is calculated. According to the positive or negative sign of the angle difference θ, a movement amount control signal C is generated to control behaviors of a software object  301 . Some exemplary behaviors of the software object  301  to be controlled in response to the movement amount control signal C are shown in  FIGS. 4A ,  4 B and  5 , which will be described later. In a case that θ=θ 1 −θ 2 &lt;0, the rotational movement amount has a negative sign. Whereas, the rotational movement amount has a positive sign if θ=θ 1 −θ 2 &gt;0. 
     An implementation example of controlling the behaviors of the software object  301  according to the angle difference θ will be illustrated with reference to  FIG. 3A  and  FIG. 3B . In this embodiment, the software object  301  is a volume control key. The behaviors of the software object  301  to be controlled include displacement amount and displacement direction of the volume control key. 
     As shown in  FIG. 3A , the first finger F 1  is stayed at a touch position of the touch pad  10  as a reference point, the second finger F 2  is moved from a initial position to a destination position in a clockwise direction M 11 . As previously described in  FIGS. 2A˜2B , a movement amount control signal C is generated. In response to the movement amount control signal C, the volume control indicator of the volume control key  301  moves downwardly (i.e. in a clockwise direction M 12 ). On the contrary, as shown in  FIG. 3B , if the second finger F 2  is moved from an initial position to a destination position in a counterclockwise direction M 21 , the volume control indicator of the volume control key  301  moves upwardly (i.e. in a counterclockwise direction M 22 ). 
     Another implementation example of controlling the behaviors of the software object  301  according to the angle difference θ will be illustrated with reference to  FIG. 4A  and  FIG. 4B . In this embodiment, the software object  301  is for example a digital image. The behaviors of the software object  301  to be controlled include rotational amount and rotational direction of the digital image. 
     As shown in  FIG. 4A , the first finger F 1  is stayed at a touch position of the touch pad  10  as a reference point, the second finger F 2  is moved from a initial position to a destination position in a clockwise direction M 31 . As is also described in  FIGS. 2A˜2B , a movement amount control signal C is generated. In response to the movement amount control signal C, the image  301  is rotated in the clockwise direction M 32 . On the contrary, as shown in  FIG. 4B , if the second finger F 2  is moved from an initial position to a destination position in a counterclockwise direction M 41 , the image  301  is rotated in the counterclockwise direction M 42 . 
       FIG. 5  is schematic block diagram illustrating an interpreting system of the touch pad according to the present invention. The interpreting system of  FIG. 5  includes the touch pad  10 , a display body  20  and a host  30 . 
     The touch pad  10  is communicated with the host  30 , and includes a touch structure  101  and a controller  102 . The controller  102  is electrically communicated with the touch structure  101  and the host  30 . The touch structure  101  is communicated with the host  30 . For example, the lower surface of the touch structure  101  can be combined with the display body  20  by a mechanical assembling action M, as is shown in  FIG. 5 . Alternatively, the touch structure  101  can be electrically connected with the display body  20  (not shown). When the first finger F 1  or the second finger F 2  are respectively placed on first and second touch points on the upper surface of the touch pad  10 , a first touching signal S 1  and a second touching signal S 2  are asserted to the controller  102 . When the second finger F 2  is moved to and stayed at a third touch point of the touch pad  10 , a third touching signal S 3  is asserted to the controller  102 . 
     When the touching signals S 1 , S 2  and S 3  are received by the controller  102 , a first position coordinate (X 1 , Y 1 ), a second position coordinate (X 2 , Y 2 ) and a third position coordinate (X 3 , Y 3 ) are respectively generated. With the first position coordinate (X 1 , Y 1 ) serving as a reference point, a first angle θ 1  of the second position coordinate (X 2 , Y 2 ) and a second angle θ 2  of the third position coordinate (X 3 , Y 3 ) are calculated. According to the positive or negative sign of the angle difference θ, a movement amount control signal C is asserted to the host  30 . In response to the movement amount control signal C, the host  30  can control behaviors of the display information (i.e. the software object  301 ) shown on the display body  20 . 
     In the first preferred embodiment as described in  FIGS. 1 ,  2 ,  3  and  4 , the software object  301  is rotated in either a clockwise direction or counterclockwise direction according to the angle difference. Nevertheless, the software object  301  can be controlled according to the slope of line through different touch points, thereby increasing the computing speed. 
     Hereinafter, another embodiment of operating a touch pad according to the present invention will be illustrated with reference to the flowchart of  FIG. 6  and the two-dimensional coordinate diagram of  FIG. 7 . 
     When a first object (e.g. a first finger F 1 ) is placed on a touch position of the touch pad  10  (Step B 1 ), the coordinate of the touch point is detected so as to assert a first position coordinate (X 1 , Y 1 ) (Step B 2 ). 
     In Step B 3 , when a second object (e.g. a second finger F 2 ) is placed on another touch point of the touch pad  10 , the coordinate of the touch point is detected so as to assert a second position coordinate (X 2 , Y 2 ). 
     In Step B 4 , when the second finger F 2  is moved to and stayed at a further touch point of the touch pad  10 , the coordinate of the touch point is detected so as to assert a third position coordinate (X 3 , Y 3 ). In this embodiment, the second finger F 2  is moved from the initial position (i.e. the second position coordinate (X 2 , Y 2 )) to a destination position (i.e. the third position coordinate (X 3 , Y 3 )) in a clockwise direction M 11 . 
     In Step B 5 , a first slope S 112  of the line through the first position coordinate (X 1 , Y 1 ) and the second position coordinate (X 2 , Y 2 ) is measured and defined as a first movement amount index, i.e. S 112 =(Y 2 −Y 1 )/(X 2 −X 1 ). Likewise, a second slope S 113  of the line through the first position coordinate (X 1 , Y 1 ) and the third position coordinate (X 3 , Y 3 ) is measured and defined as a second movement amount index, i.e. S 113 =(Y 3 −Y 1 )/(X 3 −X 1 ). Likewise, a third slope S 123  of the line through the second position coordinate (X 2 , Y 2 ) and the third position coordinate (X 3 , Y 3 ) is measured and defined as a third movement amount index, i.e. S 123 =(Y 2 −Y 3 )/(X 2 −X 3 ). 
     In Step B 6 , if the first slope S 112 ≧0, the second slope S 113 ≧0, the third slope S 123 &lt;0, (Y 2 −Y 3 )&gt;0 and (X 2 −X 3 )&lt;0, a movement amount control signal C is generated to control a first rotational action (e.g. a clockwise rotational action) of the software object  301 . Alternatively, if the first slope S 112 ≦0, the second slope S 113 ≦0, the third slope S 123 &gt;0, (Y 2 −Y 3 )&lt;0 and (X 2 −X 3 )&lt;0, the movement amount control signal C is also generated to control the first rotational action (e.g. a clockwise rotational action) of the software object  301 . 
     In Step B 7 , if the first slope S 112 ≧0, the second slope S 113 ≧0, the third slope S 123 &lt;0, (Y 2 −Y 3 )&lt;0 and (X 2 −X 3 )&gt;0, a movement amount control signal C is generated to control a second rotational action (e.g. a counterclockwise rotational action) of the software object  301 . Alternatively, if the first slope S 112 ≦0, the second slope S 113 ≦0, the third slope S 123 &gt;0, (Y 2 −Y 3 )&gt;0 and (X 2 −X 3 )&gt;0, the movement amount control signal C is also generated to control the second rotational action (e.g. a counterclockwise rotational action) of the software object  301 . 
     Hereinafter, another embodiment of operating a touch pad according to the present invention will be illustrated with reference to the flowchart of  FIG. 8  and the two-dimensional coordinate diagram of  FIG. 9 . In this embodiment, two fingers are employed to zoom in or out of a digital image. 
     When a first object (e.g. a first finger F 1 ) is placed on a touch position of the touch pad  10  (Step C 1 ), the coordinate of the touch point is detected so as to assert a first position coordinate (X 1 , Y 1 ) (Step C 2 ). 
     In Step C 3 , when a second object (e.g. a second finger F 2 ) is placed on another touch point of the touch pad  10 , the coordinate of the touch point is detected so as to assert a second position coordinate (X 2 , Y 2 ). 
     In Step C 4 , when the second finger F 2  is moved to and stayed at a further touch point of the touch pad  10 , the coordinate of the touch point is detected so as to assert a third position coordinate (X 3 , Y 3 ). In this embodiment, the second finger F 2  is moved from the initial position (i.e. the second position coordinate (X 2 , Y 2 )) to a destination position (i.e. the third position coordinate (X 3 , Y 3 )) in a zoom-out direction M 61 . 
     In Step C 5 , a first slope S 212  of the line through the first position coordinate (X 1 , Y 1 ) and the second position coordinate (X 2 , Y 2 ) is measured and defined as a first movement amount index, i.e. S 212 =(Y 2 −Y 1 )/(X 2 −X 1 ). Likewise, a second slope S 213  of the line through the first position coordinate (X 1 , Y 1 ) and the third position coordinate (X 3 , Y 3 ) is measured and defined as a second movement amount index, i.e. S 213 =(Y 3 −Y 1 )/(X 3 −X 1 ). Likewise, a third slope S 232  of the line through the third position coordinate (X 3 , Y 3 ) and the second position coordinate (X 2 , Y 2 ) is measured and defined as a third movement amount index, i.e. S 232 =(Y 2 −Y 3 )/(X 2 −X 3 ). 
     In Step C 6 , if the first slope S 212 ≧0, the second slope S 213 ≧0, the third slope S 232 ≧0, (X 2 −X 1 )&gt;(X 3 −X 1 ), and (Y 2 −Y 1 )&gt;(Y 3 −Y 1 ), a movement amount control signal C is generated to control a first zoom in/out action (e.g. a zoom-out action in the direction M 61  as shown in  FIG. 10A ) of the software object  301 . Alternatively, if the first slope S 212 &lt;0, the second slope S 213 &lt;0, the third slope S 232 &lt;0, (X 2 −X 1 )&gt;(X 3 −X 1 ), and (Y 2 −Y 1 )&gt;(Y 3 −Y 1 ), the movement amount control signal C is also generated to control the first zoom in/out action (e.g. a zoom-out action in the direction M 61  as shown in  FIG. 10A ) of the software object  301 . 
     In Step C 7 , if the first slope S 212 ≧0, the second slope S 213 ≧0, the third slope S 232 ≧0, (X 2 −X 1 )&lt;(X 3 −X 1 ), and (Y 2 −Y 1 )&lt;(Y 3 −Y 1 ), a movement amount control signal C is generated to control a second zoom in/out action (e.g. a zoom-in action in the direction M 71  as shown in  FIG. 10B ) of the software object  301 . Alternatively, if the first slope S 212 &lt;0, the second slope S 213 &lt;0, the third slope S 232 &lt;0, (X 2 −X 1 )&lt;(X 3 −X 1 ), and (Y 2 −Y 1 )&lt;(Y 3 −Y 1 ), the movement amount control signal C is also generated to control the second zoom in/out action (e.g. a zoom-in action in the direction M 71  as shown in  FIG. 10B ) of the software object  301 . 
     Another implementation example of controlling the behaviors of the software object  301  will be illustrated with reference to  FIG. 10A  and  FIG. 10B . In this embodiment, the software object  301  is a digital image. The behaviors of the software object  301  to be controlled include zoom in/out amount and zoom in/out direction of the digital image. As shown in  FIG. 10A , the first finger F 1  is stayed at a touch position of the touch pad  10  as a reference point and the second finger F 2  comes closer to the first finger F 1  in the direction M 61 , so that the image  301  is squeezed in the zoom out direction M 62 . On the contrary, as shown in  FIG. 10B , the first finger F 1  is stayed at a touch position of the touch pad  10  as a reference point and the second finger F 2  is spread apart from the first finger F 1  in the direction M 71 , so that the image  301  is stretched in the zoom in/out direction M 72 . 
     Hereinafter, a further embodiment of operating a touch pad according to the present invention will be illustrated with reference to the flowchart of  FIG. 11  and the two-dimensional coordinate diagram of  FIG. 12 . In this embodiment, two fingers are simultaneously moved to zoom in or out of an image. 
     When a first object (e.g. a first finger F 1 ) is placed on a touch position of the touch pad  10  (Step D 1 ), the coordinate of the touch point is detected so as to assert a first position coordinate (X 1 , Y 1 ) (Step C 2 ). 
     In Step D 3 , when a second object (e.g. a second finger F 2 ) is placed on another touch point of the touch pad  10 , the coordinate of the touch point is detected so as to assert a second position coordinate (X 2 , Y 2 ). 
     In Step D 4 , the first finger F 1  and the second finger F 2  are simultaneously moved. When the second finger F 2  and the first finger F 1  are moved to and stayed at specified touch points of the touch pad  10 , the coordinates of the touch points are detected so as to respectively assert a third position coordinate (X 3 , Y 3 ) and a fourth position coordinate (X 4 , Y 4 ). In this embodiment, the second finger F 2  is moved from the initial position (i.e. the second position coordinate (X 2 , Y 2 )) to the destination position (i.e. the third position coordinate (X 3 , Y 3 )) in a first zoom-out direction M 81 . In addition, the first finger F 1  is moved from the initial position (i.e. the first position coordinate (X 1 , Y 1 )) to the destination position (i.e. the fourth position coordinate (X 4 , Y 4 )) in a second zoom-out direction M 82 . 
     In Step D 5 , a first slope S 312  of the line through the first position coordinate (X 1 , Y 1 ) and the second position coordinate (X 2 , Y 2 ) is measured and defined as a first movement amount index, i.e. S 312 =(Y 2 −Y 1 )/(X 2 −X 1 ). Likewise, a third slope S 332  of the line through the third position coordinate (X 3 , Y 3 ) and the second position coordinate (X 2 , Y 2 ) is measured and defined as a third movement amount index, i.e. S 332 =(Y 2 −Y 3 )/(X 2 −X 3 ). Likewise, a fourth slope S 314  of the line through the first position coordinate (X 1 , Y 1 ) and the fourth position coordinate (X 4 , Y 4 ) is measured and defined as a fourth movement amount index, i.e. S 314 =(Y 4 −Y 1 )/(X 4 −X 1 ). Likewise, a fifth slope S 343  of the line through the fourth position coordinate (X 4 , Y 4 ) and the third position coordinate (X 3 , Y 3 ) is measured and defined as a fifth movement amount index, i.e. S 343 =(Y 3 −Y 4 )/(X 3 −X 4 ). 
     In Step D 6 , if the first slope S 312 ≧0, the third slope S 332 ≧0, the fourth slope S 314 ≧0, the fifth slope S 343 ≧0, (X 2 −X 1 )&gt;X 3 −X 4 ), and (Y 2 −Y 1 )&gt;(Y 3 −Y 4 ), a movement amount control signal C is generated to control a zoom-out action of the software object  301  in the directions M 81  and M 82  (as shown in  FIG. 12 ). Alternatively, if S 312 &lt;0, the third slope S 332 &lt;0, the fourth slope S 314 &lt;0, the fifth slope S 343 &lt;0, (X 2 −X 1 )&gt;(X 3 −X 4 ), and (Y 2 −Y 1 )&gt;(Y 3 −Y 4 ), the movement amount control signal C is also generated to control the zoom-out action of the software object  301  in the directions M 81  and M 82  (as shown in  FIG. 12 ). 
     In Step D 7 , if the first slope S 312 ≧0, the third slope S 332 ≧0, the fourth slope S 314 ≧0, the fifth slope S 343 ≧0, (X 2 −X 1 )&lt;(X 3 −X 4 ), and (Y 2 −Y 1 )&lt;(Y 3 −Y 4 ), a movement amount control signal C is generated to control a zoom-in action (not shown) of the software object  301 . Alternatively, if S 312 &lt;0, the third slope S 332 &lt;0, the fourth slope S 314 &lt;0, the fifth slope S 343 &lt;0, (X 2 −X 1 )&lt;(X 3 −X 4 ), and (Y 2 −Y 1 )&lt;(Y 3 −Y 4 ), the movement amount control signal C is also generated to control the zoom in/out action (not shown) of the software object  301 . 
     From the above embodiment, the method of the present invention can use two fingers to operate the touch pad to rotate the software object at a specified angle, move the software object along multi-directions with two fingers, and zoom in/out the software object. 
     While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.