Abstract:
An electromagnetic pointer is disclosed. The electromagnetic pointer includes at least one pen tube assembly, a pen tip, a core holder configured in the pen tube assembly with a surrounding coil, a ferrite core, an elastomer, a touch pin configured in the core holder and the pen tube assembly and a circuit board.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The entire contents of Taiwan Patent Application No. 101221467, filed on Nov. 6, 2012, from which this application claims priority, are incorporated herein by reference. 
       FIELD OF THE INVENTION 
       [0002]    The present invention generally relates to an electromagnetic pointer, more particularly to an electromagnetic pointer with a variable inductor. 
       BACKGROUND OF THE INVENTION 
       [0003]    Input apparatuses such as smart mobile devices (smart phones), digitizers or tablets or e-books/green books usually are used with electromagnetic pointers or styluses so as to perform input function. 
         [0004]    An input apparatus includes a plurality of antennas or sensor coils forming a sensing plane arranged under a work surface or a screen of the input apparatus. During the operation of an electromagnetic pointer, the coordinates of the electromagnetic pointer are obtained through the transmitting and receiving of electromagnetic waves between the circuit of the electromagnetic pointer and the antennas or the sensor coils of the input apparatus. 
         [0005]    The circuit of an electromagnetic pointer usually comprises an inductor, a capacitor and relative components enclosed in a case. The inductor constituted by a ferrite core winded with a metal coil and the capacitor constitute the circuit to transmit and receive electromagnetic waves with the antennas or sensor coils, The frequency variation of the circuit is achieved via changing the capacitance and/or the inductance so that the design of the pointer can choose either the inductor or capacitor to be variable or adjustable according to the requirement. 
         [0006]    The invention provides an electromagnetic pointer with a variable inductor. 
       SUMMARY OF THE INVENTION 
       [0007]    One object of the invention is to provide an electromagnetic pointer with a variable inductor which utilizes a contact force applied upon to alter the contact status between the conductive terminals of the circuit board and the conductive device to initiate the function of the electromagnetic pointer when an electromagnetic pointer is in use. 
         [0008]    The invention provides an electromagnetic pointer comprising at least one pen case, a pen tip, a core holder and a coil winding the core holder, a ferrite core, an elastomer, a touch pin and a circuit board. The pen tip is configured to be located in the pen case and extending out from the pen case. The core holder and the coil winding the core holder are configured to be located in the pen case. The ferrite core is configured to be located in the core holder and the pen case and contacts the pen tip. The elastomer and the touch pin are configured to be located in the core holder and the pen case. The elastomer is between the ferrite core and the touch pin. One end of the touch pin extends out from the core holder. The circuit board has a plurality of conductive terminals on one end thereof. The conductive terminals are adjacent the touch pin. A conductive device is between the conductive terminals and the touch pin, and the coil connects to the circuit board. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  shows an electromagnetic pointer according to one embodiment of the present invention. 
           [0010]      FIG. 1A  shows a cross-sectional view of an electromagnetic pointer according to one embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0011]    Reference will now be made in detail to specific embodiments of the invention. Examples of these embodiments are illustrated in accompanying drawings. While the invention will be described in conjunction with these specific embodiments, it will be understood that it is not intended to limit the invention to these embodiments, On the contrary, it is intended to cover alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may be practiced without some or all of these specific details. In other instances, well known process operations are not described in detail in order not to unnecessarily obscure the present invention. 
         [0012]      FIG. 1  shows an electromagnetic pointer according to one embodiment of the present invention.  FIG. 1A  shows a cross-sectional view of an electromagnetic pointer according to one embodiment of the present invention. As shown in  FIG. 1 , the electromagnetic pointer  100  comprises a switch  102 , pen cases  104   a  and  104   b  (first and second pen cases), and a pen tip  106 . 
         [0013]    In the embodiment shown in  FIG. 1A , the electromagnetic pointer  100  further comprises a circuit board  118 , a core holder  105 , a holder  106 , holders  120   a  and  120   b,  an elastomer  110 , a touch pin  112 , a ferrite core  108  and a conductor device  114 . The pen cases  104   a  and  104   b  comprise hollow pen shell components made of non-metal materials to accommodate the circuit board  118 , the core holder  105 , the holder  106 , the holders  120   a  and  120   b,  the elastomer  110 , the touch pin  112 , the ferrite core  108 . The diameters of the pen cases  104   a  and  104   b  can be smaller than about 6 mm, and is preferably about 5.5 mm, but is not limited to 5.5 mm. The diameters of the pen cases  104   a  and  104   b  can also be larger than about 6 mm. 
         [0014]    In one embodiment of the invention, the circuit board  118  comprises a printed circuit board with a LC circuit and a controller so that the electromagnetic pointer is able to transmit electromagnetic signals to an electromagnetic input apparatus, or to receive electromagnetic signals from electromagnetic antenna loops or sensor coils of the electromagnetic input apparatus. The electromagnetic input apparatus comprises a smart mobile communication device, digitizer or tablet or eBook. 
         [0015]    In one embodiment of the invention, the pen tip  106  penetrates through the pen case  104   a  and extends from one opening of one end of the pen case  104   a.  The pen tip  106  comprises one contact end used for contacting the contact surface of the input apparatus and a second end with a larger cross sectional area comparing to that of the contact end. The cross sectional area of the second end is larger than the inner diameter of the end of the pen case  104   a  toward the pen tip so that the pen tip  106  will not completely penetrate through the pen case  104   a  and will be limited inside the pen case  104   a.    
         [0016]    In one embodiment of the invention, the ferrite core  108  is configured to be located in the hollow pen case  104   a  and to be arranged after the pen tip  106 . The hollow core holder  105  is configured to be located in the hollow pen case  104   a.  The hollow core holder  105  is used to secure the ferrite core  108  so that the ferrite core  108  is able to be moved axially inside the pen case  104   a.  The elastomer  110  and the touch pin  112  are configured to be located in the core holder  105 , and the elastomer  110  is located between the ferrite core  108  and the touch pin  112 . The inner diameter of the end of the core holder  105  toward the pen tip is larger than that of the other end of the core holder  105 . The diameter or cross-sectional area of the end of the touch pin  112  toward the pen tip is larger than that of the other end of the touch pin  112 . The diameter or cross-sectional area of the other end of the touch pin  112  is larger than the inner diameter of the other end of the core holder  105  so that the touch pin  112  can be limited in the core holder  105  after the touch pin  112  is partially through the core holder  105 , 
         [0017]    In one embodiment of the invention, the circuit board  118  is configured to be secured in the pen cases  104   a  and  104   b  via the holder  116 , the core holder  105 , the holder  120   a  and  120   b.  The end of the circuit board  118  toward the pen tip of the electromagnetic pointer has a plurality of conductive terminals. The conductive device  114  is configured to be located between the circuit board  118  and the touch pin  112 . The conductive terminals of the circuit board  118  are electrically connected through the conductive device  114  after the touch pin  112  pushes the conductive device  114 . Detailed content will be further described in the following description. The switch  102  is configured to be located on the circuit board  118  and extend out from the pen case  104   a.  The switch  102  is used as a switch of the circuit board  118 . 
         [0018]    The pen tip  106  penetrates through the pen case  104   a  so that the pen tip  106  is able to slide inside the pen case  104   a.  The ferrite core  108  is configured to be located in the hollow pen case  104   a  and to be arranged after the pen tip  106 . The elastomer  110  and the touch pin  112  are configured to be located after the ferrite core  108  and inside the core holder  105 . The elastomer  110  is configured to be located between the ferrite core  108  and the touch pin  112 , The touch pin  112  is configured to be able to be moved and limited inside the core holder  105 . When the core holder  105 , the holder  116 , the switch  102 , the holders  120   a  and  120   b  and the circuit board  118  are configured to be secured in the pen cases  104   a  and  104   b,  the pen tip  106 , the ferrite core  108 , the elastomer  110  and the touch pin  112  are configured to be restricted inside the space constituted by the pen case  104   a  and the core holder  105 . 
         [0019]    In one embodiment of the invention, since the space constituted by the pen case  104   a  and the core holder  105  is constant, the moving distance of the pen tip  106 , the ferrite core  108  and the touch pin  112  is directly related to the compressibility of the elastomer  110 . 
         [0020]    In one embodiment of the invention, the conductive device  114  is configured to be located in the holder  116  and the core holder  105  and between the conductive terminals of the circuit board  118  and the end of the touch pin  112  extending out from the core holder  105 . The conductive device  114  alters the status of contact with the conductive terminals of the circuit board  118  via the pushing of the end of the touch pin  112  extending out from the core holder  105  so as to connect the conductive terminals of the circuit board  118  and change the electric properties of the circuit board  118  such as LC oscillation frequency. 
         [0021]    In one embodiment of the invention, the conductive device  114  comprises a cone spring or a conductive rubber, but is not limited to a cone spring or a conductive rubber. In one embodiment which the conductive device  114  is a cone spring, when one end of the touch pin  112  pushes the cone spring, the center of the cone spring will contact the conductive terminals on one end of the circuit board  118  to electrically connect the conductive terminals and the change the electric properties of the circuit board  118  such as LC oscillation frequency. The electrical connection between the conductive terminals is able to be used to initiate the writing function of an electromagnetic pointer, but is not limited to initiate the writing function. 
         [0022]    In one embodiment of the invention, a conductive coil is configured to wind the core holder  105 ; the conductive coil is configured to be connected to the circuit of the circuit board  118 . The conductive coil and the ferrite core  108  constitute a variable inductor. The variable inductor is configured to be connected to the LC circuit of the circuit board  118 . The inductance of the variable inductor or the frequency of the LC circuit is changed through the relative displacement between the ferrite core  108  and the conductive coil generated by the axial movement of the ferrite core  108  inside the core holder  105  with the winding conductive coil to create an induced current. The variation of the frequency is able to be used to change the line width of the trace of an electromagnetic pointer, but is not limited to the line width of the trace. 
         [0023]    In one embodiment of the invention, the switch  102  is configured to partially penetrate through the opening of the pen case  104   a  and to be located on the circuit board  118  as a switch of a circuit function thereof. The switch  102  is configured to be used as the switch of writing or erasing functions of the electromagnetic pointer, but is not limited to writing or erasing functions. 
         [0024]    It is noted that the embodiments of the invention focus on the configuration of the electromagnetic pointer rather than the function thereof. Thus the configuration of the embodiments of the invention is able to be applied any function of the electromagnetic pointer according to various requirements. The function which the configuration of the embodiments of the invention is applied to perform depends on circuit design. 
         [0025]    In one embodiment of the invention, the elastomer  110  comprises, but is not limited to, rubber or other elastic material. When an electromagnetic pointer is in use, a contact force is applied upon one end of the pen tip  106  and is transferred to the other end of the pen tip  106  and the ferrite core  108 . The ferrite core  108  compresses the elastomer  110  and pushes the touch pin  112 . The touch pin  112  pushes the conductive device  114  to alter the contact status between the conductive terminals of the circuit board  118  and the conductive device  114  to initiate the function of the electromagnetic pointer such as the writing function. When the electromagnetic pointer is not in use, there is a gap between the touch pin  112  and the conductive device  114 . 
         [0026]    Although specific embodiments of the present invention have been described, it will be understood by those of skill in the art that there are other embodiments that are equivalent to the described embodiments. Accordingly, it is to be understood that the invention is not to be limited by the specific illustrated embodiments, but only by the scope of the appended claims,