Title of Invention

A FLAT BRUSHLESS-TYPE VIBRATION MOTOR

Abstract

A flat brushless-type vibration motor comprising: a rotor made of an axially mounted permanent magnet with two or more magnetic poles; a ductile magnetic body bonded to a rear surface of the permanent magnet; three stator field coils for generating a rotating magnetic field to rotate the permanent magnet; an insulating stator to which an axial rod and the field coils are fixed; one or more pairs of hall sensors for detecting the magnetic poles and their positions of the permanent magnet; a motor controller for controlling an overall operation of the vibration motor; and eccentric means fiXed to one side of a peripheral surface of the permanent magnet.

Full Text

Technical Field The present invention relates to flat brush less-type vibration motor to be disposed in a mobile communication terminal, etc., for generating a vibration signal, and more particularly to a flat brushless-type vibration motor without brushes and a commutator, which is adopted instead of a brush-type vibration motor with the brushes and commutator, and includes eccentric means disposed on one side of the peripheral surface of a rotor made of a permanent magnet; one or more pairs of hall sensors mounted in the vibration motor so as to start and drive the vibration motor; a motor controller internally or externally disposed on the vibration motor; and a stator coil improved in arrangement so as to reduce the loss of magnetic flux as well as remove the non-operation points, thereby preventing the starting and driving disorders of the vibration motor, and improving its performance and efficiency. Background Art Generally, a vibration motor is employed inside a mobile communication terminal such as a cellular phone to notify a user of an incoming calf. A coin-shaped flat vibration motor, - greatly reduced in size and thickness, is widely used to meet the requirements of smaller size, lighter weight and lower power consumption in the mobile communication terminal. The flat vibration motor comprises mainly a permanent magnet as a fixed member and a rotor as a rotation member, and an electric connection between the power supply ( + ,-) and the rotor is made generally by brushes and a commutator. In the early days, vibration was attained using an eccentric plate mounted on the output axis of the rotation motor, cr a fan-shaped rotor made eccentric as a whole toward its one side and having three armature ceils mounted thereon with no overlapped portion therebetween. Such a fan-shaped vibration motor using the fan-shaped rotor includes an eccentric rotor having a plurality of armature coils spatially biased toward one side, an axial rod mounted in the center of the eccentric rotor, and "an axial bearing and a case, both for supporting the eccentric rotor so that it is freely rotated with the help of the axial rod and the bearing. The fan-shaped vibration motor also includes a housing rade of a bracket, a donut-shaped permanent magnet mounted en the bracket for providing magnetic flux to the eccentric rotor, brushes disposed inside the permanent magnet, a brush base inserted therein, and a commutator disposed on one surface of the eccencric rotor so as to be in sliding contact wich the top of the brushes. The vibration motor has such a structure that the eccentric rotor having the plurality of armature ceils spatially biased toward cr.e side is rotated; the permanent magnet is fixed; and the brush-type motor that receives the drive power through the brushes and commutator is adcoted, thereby leading to the following problems. Thai is, such problems are widely knevrr. chat, because the vibration motor is small in size with a diameter around 10mm, the brushes and commutator are weak in their structure and low in durability, in result, shortening the life span; the cost is increased due to difficulty in manufacturing the brushes and commutator,- and spark and noise caused hy the connection structure exercs a bad influence upon the operation of other various electronic devices. Because other conventional vibration motors used in the mobile communication terminal, etc., also use brush-type motors each having an eccentric unbalancing weight " without exceptions, thev have the same problems. Only a noise filter, etc., is currently available to resolve these problems. In addition, since the conventional vibration motors have large air gaDs between the rotor coils that cause a relatively large amount of magnetic flu;-: leakage, there are problems that the vibration motor is lowered in efficiency, and increased in power consumption, consequently reducing the lifetime of the mobile ccmcr.unicatiori terminals. Disclosure of che Invention Therefore, che present invention has been made in view of the above problems, and it is an object of the present invention to provide a flat brushless-type vibration motor without brushes and a commutator, instead of a brushiess-type vibration rxstor currently being used for a mobile comnunication terminal. It is another object of the present invention to provide a vibration motor wherein one or more pairs of hall sensors for detecting (sensing) magnetic poles and their positions of a permanent magnet rotor are disposed in a receiving space that is secured in an internal sice of a stator of the vibration motor to which two or three field coils are fixed, so as to enable the starting and driving of the vibration motor, and a controller of the vibration motor is mounted in one of two available mounting positions, one in the receiving space, and the other externally. It is a further object of the present invention to Drcvide a vibration motor wherein the hall sensors are integrated as one body with an integrated circuit (IC) element for controlling the vibration motor so as to simplify the entire circuit and reduce the manufacturing cost. It is vet another object of the present invention to provide a vibration motor wherein the stator field coils are imDroved in arrangement for reducing che loss of magnetic field; and the field coils are disposed to be overlapped with each other, or the boundary between the field coils is not coincidenc with the virtual line outwardly extending from the centerline of the axial rod in a radial direction, so as to remove the non-operation points, consequently preventina operating disorders and further improving its efficiency and performance. In accordance with the present invention, the above and other objects can be accompli shea by the prevision of a nencommutator vibration motor comprising: upper and lower cases made of ductile magnetic material; a rotor made of a permanent magnet having two or more magnetic poles or a donut-shaped permanent; a ductile magnetic body bonded to the rear surface of the permanent magnet; stator field coils for generating a rotating magnetic field to rotate the permanent magnet; an axial rod on which the permanent magnet is axially mounted with a bearing; an insulating stator to which the axial rod and the field coils are fixed; one or more pairs of hall sensors for detecting the magnetic poles and their positions of the oerrnap.ent magnet; a motor controller for controlling an overall operation of the vibration motor; and eccentric means fixed to cr.e side of the peripheral surface of the permanent magnet. Preferably, the insulating stator is defined at its one internal side with a receiving space to dispose therein one or more pairs of left and right hall sensors, the motor controller connected to the hall sensors, cr the hall sensors integrated as one body with an integrated circuit element for controliir.g the motor, so that the hall sensors disposed in the receiving space can detect (sense) and control the magnetic poles (or their variations) and their positions of the rotor permanent magnet. Preferably, the boundary between the field coils irav not be coincident with or parallel to the virtual line outwardly extending from the center of the axial rod in a radial direction. Alternatively, field coils neighboring each other are overlapped in arrangement, so as to remove the non-operation points. Preferably, the permanent magnet may be mounted eccentrically to the axial red, instead of using eccentric means bonded to one side of the peripheral surface of the permanent magnet. Preferably, the vibration motor controller may includes-, the hall sensors; OP amps for comparing and outputting signals inputted from the hail sensors; a control unit for controlling the starting and driving cf the motor; a plurality of motor drivers; and the field coils connected to the motor drivers, respectively. Preferablv, the control unit may include: a waveform shaping circuit for shaping the waveform of the signals inputted from the hall sensors; a logic circuit for determining the sequence of powers supplied to the field coils based on the shaped signal; a ducy setting circuit for determining the output duty and the power-feed timing signal from the logic circuit; and switching means for determining and changing the power-feed direction with respect lo the field coils, based on the output duty signal. Accordingly, the present invention provides a flat brushless-type vibration motor comprising: a rotor made of an axially-mounted permanent magnet with two or more magnetic poles; a ductile magnetic body bonded to a rear surface of the permanent magnet; three stator field coils for generating a rotating magnetic field to rotate the permanent magnet; an insulating stator to which an axial rod and the field coils are fixed; one or more pairs of hall sensors for detecting the magnetic poles and their positions of the permanent magnet; a motor controller for controlling an overall operation of the vibration motor; and eccentric means fixed to one side of a peripheral surface of the permanent magnet. Brief Description of the Drawings The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: Fig. 1 is an outline perspective view showing a vibration motor of a preferred embodiment according to the present invention; Figs. 2 and 3 are sectional and plane views of Fig. 1; Figs. 4 to 7 are plane views showing a vibration motor according to another embodiment of the present invention; Fig. 8 is a vertical sectional view showing the vibration motor according to another embodiment of the present invention; Fig. 9 is a plane view showing a permanent magnet (rotor) on which eccentric means is mounted; Fig. 10 is a block diagram showing a control circuit of a vibration motor controller according to the present invention; Fig. 11 is a plane view showing a vibration motor employing two field coils according to another embodiment of the present invention; Fig. 12 is a sectional view of Fig. 11; Fig. 13 is a block diagram showing a ccncrol circuit of the vibration motor shown in Fig. 11; and Fig. 14 is a timing chare regarding the ccncrol circuit of Fig. 13. Best Mode for Carrying Out the Invention Figs. 1 and 2 are perspective-outline and sectional views, respectively", showing the main pare of a flat brushiess-~ype vibration motor 2 without brushes and a commutator, according to the present invention. The vibrator motor 2 according to the present invention includes upper and lower cases 4 and 6 made of " ductile magnetic material, a permanent magnet 8 as a rotor, a ductile magnetic hedy 10 bonded to the rear surface of the permanent magnet 8, and stater field coils Cl, C2, and C3 for generating a rotating magnetic field so as to rotate the permanent magnet 8. An axial bearing 12 is fitted in the center hole cf the ductile magnetic bedy 10. An axial rod is coupled to the center hois of the ajvial bearing 12. The axial red 14 and the field coils Cl, C2, and C3 are fixed to an insulating stator 16. The vibration motor 2 also includes ens or more pairs of hall sensors (in the illustrated embodiment, HI and K2) for detecting magnetic poles and their positions of the permanent magnet S, a motor controller 18 for controlling the overall operation of the vibration motor 2, and a power-feed terminal 20 for transferring drive power and an external control signal to the vibration motor 2 ar.d the rector controller IS, respectively. A receiving space 22 is defined for disposing therein the hall sensors HI and K2 alone, or together with the motor controller 13. Eccentric means 24 is fixed to the peripheral surface of the permanent magnet 8. In the present invention, the cases 4 and 6 and the ductile magnetic body are all made of a magnetic material that shows a property of magnetisation by a magnet"s approach and demagnetization bv its removal. The cases 4 and 6 serve as a urotector of their internal parts as well as a magnetic shield. A reference numeral 26 denotes a washer. The permanent magnet 8 with two or more alternately-arranged magnetic poles (N or S) is mounted in such a manner that it faces the stator 16. Its rotation direction is determined based on the sequence of magnetic fields generated from the field coils Ci, C2, and C3 by the motor controller 18. The ductile magnetic body 10 prevents the magnetic field of the permanent magnet 8 from escaping backward as well as from being disturbed. In addition, the hall sensors HI and H2 are disposed in the receiving space 22 alone, combined with the motor controller IS as shewn in Fig. 3, or integrated into a one-chip IC element for controlling the vibration motor as shown in Fig. 5. The hail sensors HI and H2, which are disoesed to face the permanent magnab S, detect the positions or variations of magnetic poles, and then the decsoted result is inputted to the motor controller IS. That is, the hall sensors detect the rotor"s position and input the detected signals to the meter controller 13 . The motor controller 18 determines the sequence of powers supplied to the field coils CI, C2, and C3 during the operation of the vibration motor 2, based en the input signal mentioned above, for starting and driving the vibrating motor 2. The motor controller IS is positioned internally in the vibration motor 2 as shown in Figs. 3 and 5 in which it is disposed in the receiving space 22 together with the hall sensors HI and H2. The motor controller may also be externally disposed on the vibration as shown in Fig. 4 in which it is electrically connected to the hall sensors HI and As described above, the rotor includes the axial rod 14, the axial bearing 12, the permanent magnet S, and eccentric means (unbalancing weight) 24 fixed or attached tc one side of the peripheral surface of the permanent magnet IS. The axial bearing 12 is generally made of a metal bearing. The field coils CI, C2, and C3 are mace of fine-diameter conducting wires, such as enamel wires, wound to have a desired structure. Cores may be employed, and their omission is also permitted. But, it is preferable that at least two cores, or preferably three, are mounted, on the stater IS at positions ccrresponding to the permanent magnet 6 positioned above the cores. The field coils CI, CI, and C3 and the axial rod 14 are molded into the insulating scator 16 by insertion molding, and the field coils CI, CI, and C3 are connected at their end portions tc the motor contrcllsr 13 through the terminal 20. A mounting-coverage angle of the eccentric means 2 4 of 180c or more, fixedly disposed along the peripheral surface of the permanent magnet, causes a decrease in the vibration force, and, on the other hand, mounting-coverage angle of less than 20° to 3 0° causes a decrease in the efficiency of the vibration motor, resulting in its overload. Therefore, according to the present invention, it is preferable that the mounting-coverage angle is determined in the range between an angle much higher than 20" to 30° ar.d an angle much less than 180a, that is, around 1C0°. In addition, the amount of magnetic field sufficient for the smooth rotation of the vibration motor 8 is obtained when the sum of mounting-coverage angles of the field coils Ci, C2, and C2 is set tc more than I50c. The unbalancing bedy as the eccentric means 24 is aenerally made of a weighty material with high specific gravity. Since the unbalancing body is fixedly attached to the pericneral surface of the rotor, the permanent magnet 8, in is also made of non-magnetic metal or non-metal weiahtv material so as to exert no influence uocn the magnetic field of the permanent magnet S. The reason why the eccentric means 2~ is mace of weightv material is to obtain the amount of eccentriclev sufficient for causing the vibration, hue the vibration mav also be obtained ny disposing the permanent magnet 6 eccentrically tc the axial rod 14 without the unbalancing weight. Vihen the vibration motor 2 is configured such than the rotor permanent magnet B is disposed eccentrically to the axial red according to the present invention, the vibration motor car. be manufactured in small sice, removing separate eccentric means (unbalancing weight) to comply with the current s~aller-sice trend. In addition, because the eccentric means 24 car. he fixed to any ncsition of the peripheral surface of the permanent magnet 8, it has an advantage in that there is nc need tc set the fixed position, making its manufacture easier. In the stater 16 cf the present invention, the biased arrangement of the field coils CI, C2, and C2 allows the race i vine soace 22 to be formed at one side thereof for disposing therein one or more pairs of hall sensors HI and H2, or the motor controller IS combined with the hall sensors HI and K2. As shown in ?ia. 3, when the boundaries between the field coils CI, C2, and C3 are coincident with cr parallel to the virtual line 0 outwardly extending frcir, the center cf the axial red 14 in a radial direction, non-operation points may be generated. Therefore, in. the present invention, the field coils CI, C2, and C3 are disposed in the stator 16 in such a shape that the boundaries are not coincident with or carallel to the virtual line 0 as shown in Figs. 6 and 7, so as to remove the non-operation points and prevent the operation disorder of the vibration motor 8. In addition, the field coils CI, C2, and C3 are disposed in such a manner that the field coils CI and C2 are vertically overlapped as shown in Fig. 8, and also the field coils C2 and C3 are also vertically overlapped, so that: there is no in-plane boundary portion, thereby preventing operating disorders of the vibration motor 8, as well as improving its efficiency. Fig. 10 is a circuit diagram showing the controller IS of the vibration motor, according to cne embodiment of the present invention. The controller IS includes the hall sensors HI and H2, OP arrps OP1 to 0?4 for comparing and output tine signals from the hall sensors HI ana H2, and a control unit for controlling the starting and driving cf the vibration notcr 2a based on signals from the OP amps OP1 to OP4. The controller 18 also includes a plurality of motor drivers Dl, D2, and D3 for amplifying the output frcm the control unit, and the field coils CI, C2, and C3 connected to the outputs cf the motor drivers Dl, D2, and D3, respectively. The control unit includes therein a waveform shaping circuit (Schmitt-trigger circuit) for shaping the form of the signals from the hail senscrs Hi and H2, and a logic circuit for determining the sequence of powers supplied to the field coils CI, C2, and C3, based or. the shaped signal. The control unit also includes a duty setting circuit for setting the output duty and the power-feed timing signal from the logic circuit, and a switching circuit for determining and shifting the power-feed direction based on the output duty signal. The following table shows the signal outputs from the hall sensors HI and H2, for example, according to the magnetic Doles or their positions of the permanent magnet 5 when it has six magnetic poles. TABLE 1 (Example of signals from the hall sensors that detect the polarities of the permanent magnet with 6 magnetic poles) When signal "H" (active) is provided to both the address 1 of the hail sensor Kl and the address 2 of the hall sensor H2 according to the position of the permanent r.agnet S, power supply vcltage is fed to the field coil CI, starting and driving the vibration tec tor 2. When signal "H" is provided to the addresses 0 and 1 of the hall sensor HI and the address 2 of the hall sensor H2, cower supply voltage is fed to the field coil C2, starting and driving the vibration motor 2. Of course, the present invention is not limited to che above~mer.cior.ed examole, and the output state -ay be varied according to the number cf magnetic pcles of the permanent magnet 8 or its program. On che other hand, Figs. 11 and 12 ara schematic plane and sectional views showing the vibration motor 2a according to another embodiment of the present invention wherein the field coils C4 and C5 are positioned at both sides of the insulating stator 16. Its most parts are similar to those of the vibration motor 2 that errolovs three field coils CI, C2 and C3, but the field coils C4 and C5 are differently positioned in arrangement because the number of field coils C4 and C5 is c,",-o. Therefore, there are differences also in the circuit ftr supplying the control power to the tv/c field coils C4 and 15 as well as in the control timings for roc a ting smoothly the rotor (permanent magnet). That is, the vibration motor 2a includes upoer and lower cases 4 and 5, the rotor permanent magnet; 8, the ductile magnetic bed;" 10 attached to the rear surface of the rotor permanent magnet S, and the stater field coils 14 and C5 for generating the rotating magnetic field to rotate the permanent magnet S. An axial bearing 12 is coupled to the center axial hole of the ductile magnetic body 10. An axial rod 14 is coupled zo the center hole of the axial bearing 12. The axial rod 14 and the field coils C4 and C5 are fixed to an insulating stator 15. The vibration motor 2a also includes one c- more pairs of hall sensors HI and V.2 for detecting the magnetic poles and their positions of the permanent magnet S, a motor controller ISa for controlling the overall operation of the vtorat ion ir.otor 2, and a pcv:er -1 eed ter-.mal 2 0 f or transierring the drive pcv;er and the external control signal to the vibration motor 2 and the motor controller ISa, respectively. A receiving space 22 is defined ftr disposing therein the hall sensors HI and H2 alone, or together with the motor controller 18a. Eccentric mear.s 24 is fixed to the peripheral surface of the permanent magnet S. The field coils C4 and C5 may be radially disposed, respectively, in both left and right sides of the insulating stater 16 for the smooth operation of the vibration motor 2a. However, because the receiving space 22 is positioned ac one internal side of the insulating stator 16, both the field coils are positioned so as not to be directly opposite to each other, as shown in Fig. 11, being aside from the receiving space 22. The field coils C4 and CS are disposed symmetrically with respect to the vertical centerline. It is preferable that the mounting-coverage angle Si of the field coil C4 is around 90c and the angle G2 between the vertical centerline and the field coil C4 is around 15° so as not to negatively influence the starting and driving of the vibration motor 2a v/hile securing the space margin for the receiving space 22 and the hall sensors El and H2. The permanent magnet S with two or more alternately-arranged magnetic poles N and S is disposed so as to face the stator 8. The starting and the driving direction (rotation direction) are determined based en the sequence of magnetic fields generated from the field coils C4 and C5 hy the motor controller 18a. In addition, one or more pairs of hall sensors HI and H2 are disposed, facing the permanent magnet 8, in one receiving space 22 alone or combined with the met or controller I8a, or unified or integrated as one chip with an IC element for controlling the vibration motor 2a. The hall sensors Hi and H2 detect the variations or positions ;cr rotor" s ocsicior.) in the magnetic poles of the oerr.ane.nt ma-r.ec 8 and then incut then to the motor controller 13a. Fig. 13 is a block diagram showing a control circuit cf the vibration motor 2a according to another embodiment of the present invention. This is mostly similar tc the circuit shown in Fig. 10. But, since the number of field coils C4 and C5 connected to the output cf the control unit is two and the field coils C4 and C5 alternately generate the magnetic poles N and S, the number of drivers D4 and D5 having the function of changing the polarity (+,-) cf power source voltage is set tc two, and the field ceils C4 and C5 are connected to the outputs cf the driver D4 and D5, respectively. The motor controller ISa determines the shift-timing cf the voltage polarity {+) (-) applied tc the field coils C4 and C5 during one starting and driving of the vibration motor 2a, based on the position cf the rotor inputted from the hall sensors HI and K2, so as to stare and crive the vibrating motor 2. ^"r.e motor controller 15a may be positioned irtemallv in the vibration motor 2, as mentioned above, in which it is disoosec in the receiving space 22 together with the hall sensors HI and H2 - The motor controller ISa may also be externally disoosed on the vibration motor 2, in which it is electrically connected to the hall sensors Hi and H2. In addition, the control unit includes therein a waveform shaping circuit for shaping the form cf signals from the hall sensors Hi and H2, and a switching circuit and a the voltage polarity w) (-") and the sequence cf cowers supplied to the field coils C4 and CS based on the shsoed signal. In the driver D4, the polarity (-,"(-) of power supply voltage applied to the field coil C4, as well as the magnetic field cf the field coil C4,"is changed according to the output state of the terminals D and E connected to the outputs of the control "unit. Also, in the driver D5, the polarity (-; {-] of cower supoly voltage applied to the field ooil C5, as well as the magnetic field of the field coil C~, is changed according to the cutout state of the terminals F and G connected to the outputs cf the control unit. For example, when signal lH" (active) is cutputted from the output terminal D of the control unit, and signal " L" is outputtec frem the output terminal E thereof, the voltage cf polarity -) is out put ted from the output terminal Da of the driver E4 , and the voltage cf polarity (-) is cutputted from the cutout terminal Ea of the driver D4. During this period, an S-poie magnetic field is generated from the field ceil C4 . On the contrary, when signal "L" is cutputted from the output terminal D of the control unit, and signal "H" is c outputted from the output terminal E thereof, the voltage of polarity !-) is outputted iron?, the output; terminal Da of th driver E4, and the voltage of polarity (>! is outputted from the output: terminal Ea of the driver D4 . During this oericd, an M-pole magnetic field is generated front che field ceil C4. In addition, when signal lH" /active; is outputted from the output terminal F cf the control unit, signal ,L" is outputted from the output terminal G thereof, the voltage cf polarity ( + ) is outputted from the output terminal Fa of the driver D5, and the voltage of polarity (-) is outputted from the output terminal Ga of the driver D5. During this period, S-pole magnetic field is generated from the field coil C5- On the contrary, when signal "L" is outpuzced from the output terminal F of the control unit, and signal lK" is cutoutted frcm the output terminal G of thereof, the voltage of molarity (-) is outputted from the output terminal Fa of the driver D5, and the voltage of polarity ( + ) is outputted frcm the output terminal Ga cf the driver D5. During this ceriod, an K-pole magnetic field is generated from the field coil C5. Fie 14 is a timing chart illustrating the starting and driving cf the vibration motor 2a according to said another embodiment cf the present invention. That is, when the initial position signal cf the rotor inuutted to the hole sensor HI is N (NI), power supply voltage is fed tc the field coil C4 by the controller 15a to generate S-pole magnetic field, causing magnetic attraction that allows rotation of the rotor coward the field coil C-4. With the rotor being rotated about 6GC, power supply voltage is fed to the field coil C5 to generate an M-pole magnetic field, causing a magnetic force to attract the magnetic pole SI cf "he roccr. In such operation, a phase difference of 3G3 between che field ceils C4 and C5 causes continued change in the magnetic field, allowing driving of the vibration motor 2a and its eccentric rotation. In this another embodiment, the number cf field coils C4 and C5 is two, so that the stator and the control circuit may be formed in simple manner, and also che manufaccurcr.g cost and the weight may be reduced. In the present invention, a hall sensor, one cf ■magnetic-sensitive elements, is used, as an example, for detecting che magnetic ooles N and S of che permanent magnet 8. However, other magnetic-sensitive elements may also be used, such as a lead switch, a read switch, a magnetic image reflector may be forced thereon in an arrangement according to differences in reflection or chromaticitv, 0r detect-target means of the proximity" sensor may be formed thereon. Industrial Aoolicabilicv The present invention adepts a rrushless-type vibration motor without brushes and a commutator, instead of a brush-type vibration motor with brushes and a commutator. This makes the manufacturing process easier, and prevents problems experienced in the conventional vibration motor such as poor durability, short life span, and generation of spark and noise due to the connection structure, each caused by the small-size brushes and commutator. In addition, the non-operation points are removed, preventing operating disorders, and the boundary between the field coils is narrowed or the in-plane boundary portion is removed to further reduce the leakage amount of magnetic field, thus attaining lower power consumption of the vibration motor, and improving the efficiency. This results in longer lifetime of the mobile ceromunication terminal. Further, in another embodiment chat employs two field coils, the stator and the control circuit are simplified in structure to allow reduction in the manufacturing cost and the weiqht. Furthermore, the motor controller can be mounted in the internal receiving space in the vibration motor, so that the space utilization becomes excellent, and also the hall sensors and the IC element for controlling the fro cor are made as one chip, thereby reducing the nar.ufaccuring cost and improving the reliability of operation. Although the preferred erobcdirr.er.es of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various rrodifications, additions and substitutions are possible, -.■;ichcut departing from the scope and spirit of the invention as disclcsec. in the accompanying claims. 1. A flat brushless-type vibration rr.otcr comprising: a rotor made of an anially-mounted permanent magnet with two cr mere magnetic poles; a ductile magnetic: bed-.- bended :c a rear surface cf the permanent magnet ,- three scator field ceils for generating a rotating magnetic field to rotate the permanent magnet; an insulating stater to which an axial red and the field coils are fixed; one or more pairs of hall sensors for detecting the magnetic poles and their ecsitiens of the permanent magnet,- a r.ctor controller for controlling an overall operation cf the vibration, motor; and eccentric means fixed to one side of a peripheral surface of the permanent magnet. 2. The flat brushless-tvpe vibration motor according tc claim 1, v.hersin the insulating stater is defined at one internal side thereof v.-ith a receiving space, and the hall sensors are disposed in the receiving space. 3. The fiat brushless-type vibration rr.ocor according to claim 2, -.-.herein the hall sensors are connected to the rr.ttcr controller, and the meter controller is disposed in the receivir.a space. 4. The flat brushless-type vibration motor according to claim 2, wherein the hall sensors are integrated with the motor controller in the form of a one-chip IC element, and the integrated motor controller is disposed in -he receiving space. 5. The flat brushless-type vibration motor according eo claim 1 or 2, wherein at least one boundary line between the field coils is not coincident with or parallel to a virtual line outwardly extending from a center of the ay.ial red in a radial direction, whereby there is no non-operation point. 6. The flat brushless-type vibration motor according to claim I or 2, wherein the field coils neighboring each other are disposed to be overlapped with each other, whereby there is no ncr_-operation point. 7. The flat brushless-type vibration motor according to ciairt 1 or 2, wherein the rotor permanent magneo is disposed eccentrically to the axial rod so as to cause its vibraoion. E. The flat brushless-type vibration motor according to claim, - or 2, wherein the motor controller comprises: the hall sensors for detecting the position of the permanent magnet; OP amps for comparing and outputting signals inputted from the hall sensors; a control unit for controlling starting and driving of the vibration motor with reference to signal inputted from the OP amps; a plurality of motor drivers for amplifying signals outputted from the control unit; and the field coils connected to the drivers, respectively. 9. The flat brushless-type vibration motor according to claim 1, wherein the field coils are disposed, respectively, at both internal sides of the insulting stator symmetrically with respect to a vertical centerline of the insulating stator; the mounting-coverage angle of one of the field coils is around 90°; and angle between the vertical centerline and one of the field coils is around 15°. 10. A flat brushless-type vibration motor, substantially as herein described with reference to the accompanying drawings.

Documents:

1226-chenp-2004 abstract.pdf

1226-chenp-2004 claims duplicate.pdf

1226-chenp-2004 claims.pdf

1226-chenp-2004 correspondence-others.pdf

1226-chenp-2004 correspondence-po.pdf

1226-chenp-2004 description (complete) duplicate.pdf

1226-chenp-2004 description (complete).pdf

1226-chenp-2004 drawings duplicate.pdf

1226-chenp-2004 drawings.pdf

1226-chenp-2004 form-1.pdf

1226-chenp-2004 form-19.pdf

1226-chenp-2004 form-26.pdf

1226-chenp-2004 form-3.pdf

1226-chenp-2004 form-5.pdf

1226-chenp-2004 pct search report.pdf

1226-chenp-2004 pct.pdf

1226-chenp-2004 petition.pdf