Patent Publication Number: US-2013241322-A1

Title: Linear vibrator

Description:
PRIORITY 
     This application claims the benefit under 35 U.S.C. §119(a) of a Korean patent application filed on Mar. 16, 2012 in the Korean Intellectual Property Office and assigned Serial No. 10-2012-0027385 and a Korean patent application filed on Feb. 22, 2013 in the Korean Intellectual Property Office and assigned Serial No. 10-2013-0018975, the entire disclosure of each of which is hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a linear vibrator used in a mobile phone. 2. Description of the Related Art 
     With the popularization of a mobile phone, a new type of a received alarm method called vibration has been created by incoming call pollution. This new type of a received alarm method is implemented by technology in which a user is informed of an incoming call by generating vibration when an electric current is supplied to a vibrator. 
     Meanwhile, the first vibrator adopted a method of generating vibration by rotating an eccentric mass body using a motor. However, a technical object, that is, a reduced size and thinness closely related to portability, has been further advanced from the generation of vibration by rotation and thus has derived technology regarding a vibrator that linearly vibrates. In particular, technology in which vibration is generated in order to inform that a touch has been made is applied to a recent touch phone. In this case, a linear vibrator must be used because a reaction to vibration needs to be rapidly performed. An example of the linear vibrator can include Korean Patent Registration No. 10-1046044 entitled Linear Vibrator. 
     In prior arts, the poles of a permanent magnet are differently disposed in a direction in which vibration is generated and a magnetic flux is also made close to a coil by way of a plate made of a magnetic material in order to improve efficiency. In the prior arts, however, since the direction coupling both poles of the permanent magnet together is basically vertical to a direction toward the coil, some of the magnetic flux generated from the permanent magnet leaks without interfering with the magnetic flux of the coil, thereby not contributing to the vibration of the permanent magnet. This restricts the improvement of efficiency and becomes a stumbling block to a reduction in the size of a linear vibrator. 
     The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present invention. 
     SUMMARY OF THE INVENTION 
     Aspects of the present invention are to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present invention is to provide technology regarding a linear vibrator in which a direction coupling both poles of a permanent magnet together is disposed in a direction toward a coil. 
     In accordance with an aspect of the present invention, a linear vibrator is provided. The linear vibrator includes a cylindrical coil provided in the central portion of the linear vibrator and configured to generate a magnetic flux in response to an electrical signal, a permanent magnet configured in a ring shape in the outside of the coil and configured to vibrate in response to the magnetic flux generated from the coil, a vibration body coupled with the outside of the permanent magnet and configured to vibrate while operating in conjunction with the vibration of the permanent magnet, a casing configured to accommodate the coil, the permanent magnet, and the vibration body, a circuit board configured to supply the electrical signal to the coil, and a spring configured to elastically support the vibration body to the casing, wherein the inside of the permanent magnet facing the coil and the outside of the permanent magnet coming into contact with the vibration body have different poles. 
     The linear vibrator preferably may further include a fixing body made of a non-magnetic material and configured to fix the permanent magnet to the vibration body. 
     The linear vibrator preferably may further include a polepiece inserted into the inside of the coil in order to concentrate the magnetic flux on the inside of the coil. 
     The permanent magnet preferably may be split into two or more pieces when being seen in the vibration direction of the permanent magnet. 
     The vibration body preferably may include a support jaw for supporting a first end of the permanent magnet, and a second end of the permanent magnet may be supported by the spring. 
     The casing may include an upper casing and a lower casing coupled with the upper casing, wherein a first fixing hole into and to which the upper part of the polepiece is inserted and fixed is formed in the upper casing, and a second fixing hole into and to which the lower part of the polepiece is inserted and fixed is formed in the lower casing. 
     In accordance with another aspect of the present invention, a linear vibrator is provided. The linear vibrator includes a cylindrical coil provided in the central portion of the linear vibrator and configured to generate a magnetic flux in response to an electrical signal, a permanent magnet configured in a ring shape in the outside of the coil and configured to vibrate in response to the magnetic flux generated from the coil, a vibration body coupled with the outside of the permanent magnet and configured to vibrate while operating in conjunction with the vibration of the permanent magnet, a casing configured to accommodate the coil, the permanent magnet, and the vibration body, a circuit board configured to supply the electrical signal to the coil, and a spring configured to elastically support the vibration body to the casing, wherein the vibration body comprises a support jaw for supporting a first end of the permanent magnet, and a second end of the permanent magnet is supported by the spring. 
     Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a schematic exploded perspective view showing a linear vibrator according to a first exemplary embodiment of the present invention; 
         FIG. 2  is a schematic assembly cross-sectional view showing the linear vibrator of  FIG. 1  according to an exemplary embodiment of the present invention; 
         FIG. 3  is a plan view of a permanent magnet applied to the linear vibrator of  FIG. 1  which is seen in the vibration direction of the permanent magnet according to an exemplary embodiment of the present invention; 
         FIG. 4  is a schematic assembly cross-sectional view showing a linear vibrator according to another exemplary embodiment of the present invention in which a direction in which a spring is disposed is different from that of  FIG. 1 ; 
         FIGS. 5 and 6  are reference diagrams illustrating the operation of the linear vibrator of  FIG. 1  according to an exemplary embodiment of the present invention; 
         FIG. 7  is a schematic exploded perspective view showing a linear vibrator according to a second exemplary embodiment of the present invention; and 
         FIG. 8  is a schematic assembly cross-sectional view showing the linear vibrator of  FIG. 7  according to an exemplary embodiment of the present invention. 
     
    
    
     Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures. 
     DESCRIPTION OF REFERENCE NUMERALS OF PRINCIPAL ELEMENTS IN THE DRAWINGS 
       
     
       
         
           
               
               
               
             
               
                   
                   
               
             
            
               
                   
                 100, 700: linear vibrator 
                 110, 710: coil 
               
               
                   
                 120, 720: permanent magnet 
                 130: fixing body 
               
               
                   
                 140, 740: polepiece 
                 150, 750: vibration body 
               
               
                   
                 751: support jaw 
                 160, 760: spring 
               
               
                   
                 170, 770: damper 
                 180, 780: casing 
               
               
                   
                 181, 781: upper casing 
                 182, 782: lower casing 
               
               
                   
                 781a: first fixing hole 
                 782a: second fixing hole 
               
               
                   
                 190, 790: circuit board 
               
               
                   
                   
               
            
           
         
       
     
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness. 
     The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention is provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents. 
     It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a component surface” includes reference to one or more of such surfaces. 
     First Exemplary Embodiment 
       FIGS. 1 and 2  are a schematic exploded perspective view and schematic assembly cross-sectional view of a linear vibrator  100  according to a first exemplary embodiment of the present invention. 
     Referring to  FIGS. 1 and 2 , the linear vibrator  100  according to an exemplary embodiment of the present invention includes a coil  110 , a permanent magnet  120 , a fixing body  130 , a polepiece  140 , a vibration body  150 , a spring  160 , dampers  171  and  172 , a casing  180 , and a circuit board  190 . 
     The coil  110  having a cylindrical solenoid form is provided in the central portion of the linear vibrator  100  and is configured to generate a magnetic flux in response to an electrical signal generated from the circuit board  190 . 
     The permanent magnet  120  has a ring shape having a hole formed in the center thereof, and the coil  110  is inserted into the hole of the permanent magnet  120 . That is, the permanent magnet  120  is disposed in the outside of the coil  110  and is configured to vibrate up and down in response to the magnetic flux generated from the coil  110 . 
     Here, the outside of the permanent magnet  120  configured to come into contact with the vibration body  150  and placed in a direction opposite to the inside of the permanent magnet  120  that faces the coil  110  and the inside of the permanent magnet  120  have different poles. Accordingly, a direction coupling both poles of the permanent magnet  120  together is directed toward the coil  110 , so the magnetic flux generated from the permanent magnet  120  has directivity directly toward the coil  110 . 
     Referring to  FIG. 1  and  FIG. 3  showing the permanent magnet  110  seen in a vibration direction thereof, the permanent magnet  110  is split into four pieces  121  to  124 . Accordingly, the permanent magnet  110  can be easily manufactured as compared with a case where the entire ring-shaped permanent magnet is magnetized. In some exemplary embodiments, the permanent magnet may be formed of only one piece or may be formed of 2 pieces, 3 pieces, or 5 or more pieces. 
     The fixing body  130  is made of a non-magnetic material and is configured to fix the permanent magnet  120  to the vibration body  150 . The fixing body  130  can be divided into an upper part  131  and a lower part  132  facing the upper part  131 . Furthermore, the fixing body  130  also functions to maintain the arrangement of the 4 pieces  121  to  124  of the permanent magnet  120 . 
     The polepiece  140  is made of a magnetic material and is configured in a cylindrical shape. The polepiece  140  is inserted into the inside of the coil  110  and is configured to concentrate the magnetic flux of the permanent magnet  120  on the inside of the coil  110 . 
     The vibration body  150  has a hole formed in the center thereof. The vibration body  150  is coupled with the outside of the permanent magnet  120 , that is, the permanent magnet  120  is inserted into the hole of the vibration body  150 . Accordingly, the vibration body  150  is vibrated while operating in conjunction with the vibration of the permanent magnet  120 , thus increasing a vibration mass. 
     The spring  160  provides elastic force for restoring the locations of the permanent magnet  120  and the vibration body  150  by elastically supporting the vibration body  150  that vibrates up and down and also prevents the permanent magnet  120  and the vibration body  150  from colliding against the top and bottom of the casing  180  by limiting the up and down vibration width of the permanent magnet  120  and the vibration body  150 . To this end, the spring  160  has the top fixed to the casing  180  and bottom fixed to the vibration body  150 . In another exemplary embodiment, a spring  460  may be provided under a vibration body  450 , as shown in  FIG. 4 . 
     The dampers  171  and  172  are made of a ring-shaped cushion material and are configured to prevent some of vibrating parts (i.e., the permanent magnet  120 , the fixing body  130 , the vibration body  150 , and the spring  160 ) from directly coming into contact with the top or bottom of the casing  180 . 
     The casing  180  includes a receiving space S for accommodating the coil  110 , the permanent magnet  120 , the fixing body  130 , the polepiece  140 , the vibration body  150 , the spring  160 , and the dampers  171  and  172 . The casing  180  can be separated into an upper casing  181  and a lower casing  182  coupled with the upper casing  181 . The casing  180  can be made of a magnetic material in order to improve efficiency by further precluding an external leakage of the magnetic flux. 
     The circuit board  190  is provided to come in contact with the bottom of the casing  180  in order to input an electrical signal to the coil  110  and is formed in a ring shape. Accordingly, an upper and lower thickness of the linear vibrator  100  can be reduced because the bottom of the coil  110  is directly brought in contact with the bottom of the casing  180  and fixed thereto. 
     An operation of the linear vibrator  100  configured as described above is described below. 
     For example, a magnetic flux generated from the permanent magnet  120  is inputted to the polepiece  140  through the coil  110  and is then divided into up and down parts and rotated, as shown in  FIG. 5 . 
     Meanwhile, when an electrical signal generated from the circuit board  190  is inputted to the coil  110 , an electric current flows through the coil  110 . 
     When one of threads  111  wound on the coil  110  is taken into consideration, the threads  111  of the coil  110  are subject to force F in an upward or downward direction as defined by Fleming&#39;s left-hand rule in a direction in which the electric current flows (i.e., a direction in which the electric current flows at a point through which the magnetic flux passes) as shown in  FIG. 6 . As a result, the total force summed in the upward or downward direction is applied to the coil  110  formed of the threads  111 . However, since the coil  110  is fixed, the counteraction force of the summed force applied to the coil  110  is applied to the permanent magnet  120  relatively movable up and down and the vibration body  150  coupled with the permanent magnet  120 . Accordingly, the permanent magnet  120  and the vibration body  150  coupled with the permanent magnet  120  are vibrated, thus generating a vibration shock. 
     Second Exemplary Embodiment 
       FIGS. 7 and 8  are a schematic exploded perspective view and schematic assembly cross-sectional view of a linear vibrator  700  according to a second exemplary embodiment of the present invention. 
     Referring to  FIGS. 7 and 8 , the linear vibrator  700  according to an exemplary embodiment of the present invention includes a coil  710 , a permanent magnet  720 , a polepiece  740 , a vibration body  750 , a spring  760 , dampers  771  and  772 , a casing  780 , and a circuit board  790 . 
     The coil  710  generates a magnetic flux in response to an electrical signal generated from the circuit board  790 . 
     The permanent magnet  720  is configured in a ring shape having a hole formed in the center, and the coil  710  is inserted into the hole of the permanent magnet  720 . Accordingly, the permanent magnet  720  is vibrated up and down in response to the magnetic flux generated from the coil  710 . As in the first exemplary embodiment, the outside of the permanent magnet  720  configured to come into contact with the vibration body  750  and placed in a direction opposite to the inside of the permanent magnet  720  that faces the coil  710  and the inside of the permanent magnet  720  have different poles. 
     The polepiece  740  is inserted into the inside of the coil  710  in order to concentrate the magnetic flux of the permanent magnet  720  onto the inside of the coil  710 . The polepiece  740  has the top fixed to the upper casing  781  and the bottom fixed to the lower casing  782 . 
     The vibration body  750  is coupled with the outside of the permanent magnet  720  and is vibrated while operating in conjunction with the vibration of the permanent magnet  720 , thus increasing a vibration mass. In an exemplary embodiment of the present invention, the vibration body  750  includes a support jaw  751  for supporting the bottom of the permanent magnet  720 . 
     The spring  760  elastically supports the vibration body  750  that vibrates up and down. Furthermore, the edge of the inside of the spring  760  supports the top of the permanent magnet  720 . Accordingly, the permanent magnet  720  can be fixed by the vibration body  750  and the spring  760  without an additional fixing body. 
     The dampers  771  and  772  are provided to prevent some of vibrating parts (i.e., the permanent magnet  720 , the vibration body  750 , and the spring  760 ) from directly coming into contact with the top or bottom of the casing  780 . 
     The casing  780  includes a receiving space S for accommodating the coil  710 , the permanent magnet  720 , the polepiece  740 , the vibration body  750 , the spring  760 , and the dampers  771  and  772 . Furthermore, the casing  780  can be separated into an upper casing  781  and a lower casing  782  coupled with the upper casing  781 . Here, a first fixing hole  781   a  into and to which the upper part of the polepiece  740  can be inserted and fixed is formed in the upper casing  781 , and a second fixing hole  782   a  into and to which the lower part of the polepiece  740  can be inserted and fixed is formed in the lower casing  782 . That is, the upper and lower parts of the polepiece  740  are inserted into the upper casing  781  and the lower casing  782  and fixed thereto, thereby being capable of improving durability. 
     The circuit board  790  is provided to input an electrical signal to the coil  710 . 
     The present invention can have the following advantages. 
     First, since the magnetic flux of the permanent magnet is directed toward the coil, a magnetic flux that leaks without contributing to the vibration of the permanent magnet is minimized. Accordingly, efficiency can be improved and thus the size of a linear vibration can be further reduced. 
     Second, productivity can be improved because the permanent magnet is fixed by a simple structure. 
     Third, durability can be improved because a structure for fixing the polepiece is robust. 
     While the invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents.