Abstract:
A method and apparatus for producing a signal in a pen is disclosed. When at least one section of the pen is deformed, a hammer device strikes a piezo-electronic component. In response to being struck by the hammer device, the piezo-electric component generates an electric signal. The electric signal is then applied to a wire wound inductor to create an electromagnetic nearfield.

Description:
TECHNICAL FIELD OF THE INVENTION 
       [0001]    The present invention relates to a wireless touch screen pen and more particularly to a wireless touch screen pen for communicating with a PDA or touch screen using electromagnetic nearfield coupling. 
       DESCRIPTION OF RELATED ART 
       [0002]    When using a touch screen on a small device the most common approach is to use a device similar to a pen to be able to accurately manage to press a small softkey, scrollbar, etc. Recently, the Apple I-phone® has brought another approach to the market using gestures on the touch screen to add another degree of freedom to touch screen control using fingers. The downside of this is that one of the more important features of touch screen devices, such as character recognition writing, is best done with a pen like accessory. Most GUIs for modern computers are controlled by a mouse that depending on the vendor, has a number of buttons with separate function. In Windows® operating systems, a minimum of 2 buttons, in Apple® systems 1 button and in Unix/Linux 3 button mouse. The point is that the user of a touch screen device with a graphic user interface is very used to having more possibilities than a simple tap with a pen. 
         [0003]    Thus, there is a need for a wireless touch screen pen which is capable of generating at least one “click” apart from the tap of the pen on the touch screen of a device so as to increase the functionality of a touch screen pen. 
       SUMMARY OF THE INVENTION 
       [0004]    According to some embodiments of the invention, a method for producing a signal in a pen comprising the steps of: deforming at least one section of the pen wherein a hammer device strikes a piezo-electronic component when the pen is deformed; generating an electric signal in the piezo-electric component; applying the electric signal to a wire wound inductor to create an electromagnetic nearfield. 
         [0005]    According to another embodiment of the invention, a wireless touch screen pen, comprising; a piezo-electric component; a hammer device for striking the piezo-electric component when part of the pen is deformed, wherein said piezo-electric component generates an electric signal when struck by the hammer device; means for producing an electromagnetic nearfield when the electronic signal is applied to the means. 
         [0006]    Further embodiments of the invention are defined in the dependent claims. 
         [0007]    It is an advantage of embodiments of the invention that a user has several ways of communicating with a touch screen device using electromagnetic nearfield coupling. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    Further objects, features and advantages of embodiments of the invention will appear from the following detailed description of the invention, reference being made to the accompanying drawings, in which: 
           [0009]      FIGS. 1(   a )-( b ) illustrate a wireless touch screen pen according to one embodiment of the invention; 
           [0010]      FIG. 2  is a flow chart describing the operation of the pen according to one embodiment of the invention; and 
           [0011]      FIGS. 3(   a )-( b ) illustrate a wireless touch screen pen according to one embodiment of the invention; 
           [0012]      FIGS. 4(   a )-( b ) illustrate a wireless touch screen pen according to one embodiment of the invention; and 
           [0013]      FIG. 5  illustrates a wireless touch screen pen and a touch screen device according to one embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0014]    Specific illustrative embodiments of the invention will now be described with reference to the accompanying drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, the disclosed embodiments are provided so that this specification will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The terminology used in the detailed description of the particular embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. Furthermore, in the drawings like numbers refer to like elements. 
         [0015]      FIGS. 1(   a )-( b ) illustrate a wireless touch screen pen  10  according to one embodiment of the invention. The touch screen pen  10  comprises a piezo-electric component  12 , a up-converter  14 , a hammer device  16 , a modulator  20 , a filter  22  and a device for producing an electromagnetic nearfield  18 . The piezo-electric component  12  can be a piezo ceramic or a quatrz component and the invention is not limited thereto. The device  18  for producing an electromagnetic nearfield can be a wire coil located at one end of the pen  10  and the invention is not limited thereto. 
         [0016]    The operation of the touch screen pen  10  will now be described with reference to  FIG. 2 . The piezo-electric component  12  is capable of turning a mechanical deformation into an electric potential or an electric signal. According to one embodiment of the invention, the touch screen pen  10  is deformed in a manner that causes the hammer device  16  to strike the piezo-electric component  12  in step  201 . The touch screen pen  10  can be deformed in several ways and the invention is not limited thereto. First the touch screen pen  10  may be bent, as illustrated in  FIGS. 1(   a )-( b ), to a point where the spring tension on the hammer device  16  is released causing the hammer device  16  to strike the piezo-electric component  12 . Alternatively, the touch screen pen  10  may have a button  30  which when pressed by the user causes the tension on the hammer device  16  to be released resulting in the hammer device  16  striking the piezo-electric component  12  as illustrated in  FIGS. 3(   a )-( b ). Alternatively, the touch screen pen  10  may be divided into two sections  40  and  42  which can twist relative to each other. Thus, when the user twists one section of the pen, the tension on the hammer device  16  is released and the hammer device strikes the piezo-electric component  12  as illustrated in  FIGS. 4(   a )-( b ). It will be understood that the touch screen pen  10  may comprise more than one means for deforming the pen and the invention is not limited thereto. Furthermore, different resonance frequencies and/or modulation for two or more buttons, etc., on the same device makes it possible for the touch screen device to distinguish clicks from different, in this case, buttons. 
         [0017]    Returning to  FIG. 3 , when the hammer device  16  strikes the piezo-electric component  12 , the piezo-electric component  12  generates an electric signal in step  203 . Optionally, the electric signal is sent to the up-converter  14 . The up-converter  14  converts the electric signal to a suitable frequency band for example using a passive semiconductor or other materials with non-linear characteristics, e.g. various metal oxides, in step  205 . Optionally, the up-converted signal may be moduated by a modulator  20  and/or filtered by a filter  22  in steps  207  and  209  respectively. 
         [0018]    The processed signal or the original electric signal is then applied to the wire wound inductor  18  in the tip of the pen. When the processed signal is applied to the wire wound inductor  18 , a strong electromagnetic field is created at the tip of the pen  10  in step  211 . When the strong electromagnetic field is created, the electromagnetic field can be sensed by a touch screen device  50  in a variety of ways if the tip of the touch screen pen  10  is close to the touch screen device  50  as illustrated in  FIG. 5 . For example, the electromagnetic field can be detected at signal lines in the printed circuit board of the touch screen device  50  intended for other signals or in printed circuit board loops, inductors or other components dedicated for detecting the presence of the electromagnetic field. For example, a small RF detector on or off the printed circuit board can be used to recognize the detected signal and produce a basband signal indicating that a pen event (click) has occured. Already present RF processing circuit or a touch screen device could also be used for this purpose. A single or a set of unique frequencies and/or modulation for a single device will prevent devices which are close to each other from interfering with each other. Finally, the coupling to the touch screen device  50  could also be accomplished through, e.g. capacitive coupling using the strong electric fields at a sharp metallic point fed a high voltage or other similar methods. 
         [0019]    The present invention has been described above with reference to specific embodiments. However, other embodiments than the above described are equally possible within the scope of the invention. Different method steps than those described above, performing the method by hardware or software or a combination of hardware and software, may be provided within the scope of the invention. It should be appreciated that the different features and steps of the invention may be combined in other combinations than those described. The scope of the invention is only limited by the appended patent claims.