(19)
(11)EP 2 963 789 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
26.06.2019 Bulletin 2019/26

(21)Application number: 15164805.2

(22)Date of filing:  22.02.2011
(51)International Patent Classification (IPC): 
H02K 33/18(2006.01)
H02P 7/06(2006.01)
G02B 7/09(2006.01)
H02P 25/02(2016.01)
G02B 7/04(2006.01)
G02B 7/08(2006.01)
H02K 41/035(2006.01)
G11B 7/09(2006.01)

(54)

VOICE COIL MOTOR AND DRIVING METHOD THEREOF

SCHWINGSPULENMOTOR UND ANSTEUERUNGSVERFAHREN DAFÜR

MOTEUR À BOBINE ACOUSTIQUE ET SON PROCÉDÉ DE COMMANDE


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 02.11.2010 KR 20100108427

(43)Date of publication of application:
06.01.2016 Bulletin 2016/01

(60)Divisional application:
19173754.3

(62)Application number of the earlier application in accordance with Art. 76 EPC:
11838126.8 / 2636132

(73)Proprietor: LG Innotek Co., Ltd.
Seoul, 04637 (KR)

(72)Inventor:
  • Park, Sangok
    100-714 Seoul (KR)

(74)Representative: Zardi, Marco 
M. Zardi & Co. SA Via Pioda 6
6900 Lugano
6900 Lugano (CH)


(56)References cited: : 
JP-A- 2009 169 010
US-A1- 2004 001 603
US-A- 4 297 537
US-B1- 6 414 931
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    [Technical Field]



    [0001] The present invention relates to a voice coil motor and a driving method of a voice coil motor.

    [Background Art]



    [0002] Recently, a mobile terminal embedded with a super small digital camera has been developed. A super small digital camera formed on a conventional mobile terminal is disadvantageous in that a gap between an image sensor adapted to change an outside light to a digital image or a digital picture and a lens cannot be adjusted. However, a lens driving device such as a voice coil motor adapted to adjust a gap between an image sensor and a lens has been recently developed to enable obtainment of an improved digital image or digital picture in a super small digital camera.

    [0003] Generally, a voice coil motor is configured such that a lens is mounted therein, a bobbin arranged on a base is upwardly moved from the base to adjust a gap between a lens and an image sensor mounted on a rear surface of the base. The bobbin of the voice coil motor is coupled with a leaf spring to allow the bobbin to contact the base at all times by way of elasticity of the leaf spring when the voice coil motor is not operated.

    [0004] That is, the bobbin of the conventional voice coil motor is driven only to one upward direction relative to the base. The conventional voice coil motor that drives to one direction relative to the base inevitably and disadvantageously needs a driving force larger than that of the elasticity of the leaf spring and a self weight of the bobbin in order to drive the voice coil motor, resulting in increased power consumption of the voice coil motor.

    [0005] Another disadvantage is that size of a coil wound on the bobbin or a magnet is increased by a driving force larger than the self weight of bobbin and elasticity of the leaf spring to drive the voice coil motor, resulting in an increased overall size of the voice coil motor.

    [0006] Still another disadvantage is that a focus between the lens and the image sensor is not precisely adjusted to degrade quality of an image, if the leaf spring is deformed. US 6414931 B1 discloses a recording/reproducing apparatus for an optical recording medium in which a laser light beam is illuminated on an optical recording medium using a double-lens type objective lens made up of at least a first lens and a second lens to record and/or reproduce the information. JP 2009 169010 A discloses a method of focusing a lens of a movable section of an imaging optical system on a desired position in a short time during lens position control without causing an increase in the size of an arrangement or in power consumption.

    [Disclosure]


    [Technical Problem]



    [0007] The present invention is directed to a voice coil motor and a driving method of a voice coil motor configured to further improve the power consumption, size and quality of image in the voice coil motor.

    [Technical Solution]



    [0008] The invention is defined by the features of device claim 1. The dependent claims recite advantageous embodiments of the invention.

    [0009] In some exemplary embodiment of the present invention, the elastic member may include a first elastic member connected to a bottom end of the bobbin and a second elastic member connected to an upper end opposite to the bottom end
    of the bobbin.

    [0010] In some exemplary embodiment of the present invention, each of the first and second elastic members may include an inner elastic unit coupled to the bobbin, an outer elastic unit connectively coupled to the stator, and a connection elastic unit connecting the inner and outer elastic units.

    [0011] In some exemplary embodiment of the present invention, the inner elastic unit may be arranged at a bottom surface of the outer elastic unit by droop caused by a self weight of the mover.

    [0012] In some exemplary embodiment of the present invention, the inner elastic unit may be arranged at a position higher than that of the outer elastic unit in consideration of the droop by the self weight of the mover, and the first and second elastic members may be arranged in parallel with an upper surface of the base.

    [0013] In some exemplary embodiment of the present invention, the voice coil motor may further include a cover can fixed at the base to cover the mover and the stator, and shock absorption members may be arranged at any one of the base opposite to the bobbin and an inner surface of the cover can opposite to the bobbin.

    [0014] In some exemplary embodiment of the present invention, first and second shock absorption members may be arranged on the base opposite to the bobbin and the inner surface of the cover can opposite to the bobbin.

    [0015] In some exemplary embodiment of the present invention, the shock absorption members may include any one of a sponge, a synthetic resin having an elasticity and a rubber.

    [0016] In another general aspect of the present invention, a voice coil motor is provided, the voice coil motor characterized by: a stator including a magnet generating a first electromagnetic field; a mover including a bobbin formed with a hollow hole through which light passes and a coil formed on a periphery of the bobbin that generates a second electromagnetic field responsive to the first electromagnetic field; a base fixed at the stator and formed with an opening through which the light passes; and an elastic member elastically supporting the bobbin, wherein the bobbin supported by the elastic member is driven to any one direction of a first direction distancing from the base by an ascending power generated by the first and second electromagnetic fields, and a second direction approaching the base by a descending power generated by the first and second electromagnetic fields.

    [0017] In some exemplary embodiment of the present invention, a forward current may be applied to the coil when the bobbin is driven to the first direction, and a backward current that flows in opposition to the forward current may be applied to the coil when the bobbin is driven to the second direction.

    [0018] In some exemplary embodiment of the present invention, the voice coil motor may drive the bobbin to any one direction of the first direction and the second direction by adjusting a voltage difference across the coil.

    [0019] In still another general aspect of the present invention, a voice coil motor is provided, the voice coil motor characterized by: a stator including a magnet generating a first electromagnetic field; a mover including a bobbin formed with a hollow hole through which light passes and a coil formed on a periphery of the bobbin that generates a second electromagnetic field responsive to the first electromagnetic field; a base fixed at the stator and formed with an opening through which the light passes; at least one elastic member elastically supporting the bobbin and forming a gap between a bottom end of the bobbin and an upper surface of the base; and a driving module including a control unit generating an ascending control signal for ascending the bobbin and a descending control signal for descending the bobbin, and a current providing unit providing either a forward current or a backward current to the coil in response to the ascending control signal and the descending control signal of the control unit.

    [0020] In some exemplary embodiment of the present invention, the current providing unit may include a first unit circuitry in which first and second switch elements are connected in series, and a second unit circuitry in which third and fourth switch elements are connected in series, wherein the first and second unit circuitries are electrically connected in parallel relative to power, a first distal end of the coil is connectively interposed between the first and second switch elements, and a second distal end of the coil is connectively interposed between the third and fourth switch elements.

    [0021] In some exemplary embodiment of the present invention, the ascending control signal may be provided to the first and second switch elements to apply the forward current to the coil, and the descending control signal may be provided to the third and fourth switch elements to apply the backward current to the coil.

    [0022] In a still further general aspect of the present invention, there is provided a method for driving a voice coil motor, the method characterized by: moving a bobbin to a reference position by applying a first current to a coil wound on the bobbin embedded with a lens and elastically supported by an elastic member by being distanced from a base; applying to the coil a second current flowing in a direction opposite to the first current to distance the bobbin from the reference position; and stopping the bobbin at a position corresponding to an optimum focus by constantly maintaining an amount of the second current when the optimum focus is formed between the lens and an image sensor.

    [0023] In some exemplary embodiment of the present invention, the reference position may be one of an upper surface of the base and an inner lateral surface of a cover can covering the bobbin.

    [0024] In some exemplary embodiment of the present invention, the amount of second current in the step of distancing the bobbin from the reference position may continuously increase.

    [0025] In some exemplary embodiment of the present invention, the step of stopping the bobbin at a position corresponding to an optimum focus may include moving the bobbin to a position deviated from the position of the optimum focus, and returning the bobbin to the position of the optimum focus by re-applying the first current to the coil.

    [0026] In a still further general aspect of the present invention, there is provided a method for driving a voice coil motor, the method characterized by: moving a bobbin to a reference position by applying a first current to a coil wound on the bobbin embedded with a lens and elastically supported by an elastic member by being distanced from a base; calculating a data for forming an optimum focus between a lens and an image sensor module based on an object; and moving the bobbin to the reference position based on the data by applying to the coil a second current flowing in opposition to the first current relative to the data.

    [0027] In some exemplary embodiment of the present invention, the second current may be an amount of a current having a predetermined intensity.

    [0028] Technical problems to be solved by the present invention are not restricted to the above-mentioned description, and any other technical problems not mentioned so far will be clearly appreciated from the following description by skill in the art.

    [Advantageous Effects]



    [0029] The voice coil motor and a method for driving the voice coil motor according to the present invention has an advantageous effect in that a bobbin mounted with a lens is distanced from an upper surface of a base mounted with an image sensor, and a mover including the bobbin is driven to a direction distanced from the base or a direction approaching the base by applying a forward current or a backward current to a coil block wound on the bobbin, to reduce power consumption of the voice coil motor and to adjust a focus between the lens and the image sensor within a rapid period of time.

    [0030] The voice coil motor and a method for driving the voice coil motor according to the present invention has another advantageous effect in that a contact noise generated by driving of the bobbin can be reduced.

    [Description of Drawings]



    [0031] Non-limiting exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like reference numerals refer to like parts or portions throughout the description of several views of the drawings.

    FIG. 1 is a cross-sectional view illustrating a voice coil motor according to an exemplary embodiment of the present invention.

    FIG. 2 is a partial enlarged view of 'A' of FIG.1.

    FIG. 3 is a cross-sectional view illustrating a conventional voice coil motor to compare with that of the exemplary embodiment of the present invention.

    FIG. 4 is a graph illustrating a relation between a driving current amount for driving the voice coil motor of FIG.3 and a moving amount according to the present invention.

    FIG. 5 is a schematic cross-sectional view illustrating a voice coil motor according to an exemplary embodiment of the present invention.

    FIG. 6 is a graph illustrating a relation between a driving current amount for driving the voice coil motor of FIG.5 and a moving amount according to the present invention.

    FIG. 7 is a block diagram illustrating a driving circuit for ascending or descending a mover of a voice coil motor according to an exemplary embodiment of the present invention.

    FIGS. 8 and 9 are block diagrams illustrating a forward direction current and a backward direction current applied to a coil block by a driving circuit.

    FIGS. 10 and 11 are graphs illustrating a method for driving a voice coil motor according to the present invention.


    [Best Mode]



    [0032] The advantages, features and methods for achieving the foregoing will be apparent from the accompanying drawings and exemplary embodiments that follow.

    [0033] Embodiments of the present invention are described below by way of example only. These examples represent the best ways of putting the invention into practice that are currently known to the Applicant although they are not the only ways in which this could be achieved.

    [0034] This invention may be embodied in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

    [0035] FIG.1 is a cross-sectional view illustrating a voice coil motor according to an exemplary embodiment of the present invention, and FIG.2 is a partial enlarged view of 'A' of FIG.1.

    [0036] Referring to FIGS. 1 and 2, a voice coil motor (600) may include a stator (100), a mover (200), a base (300) and an elastic member (400).

    [0037] The stator (100) may include a yoke (120) and a magnet (130). The stator (100) generates a first electromagnetic field for driving the mover (200. described later). The yoke (120) may include a yoke upper plate (122) and a yoke lateral plate (124). The yoke (120) functions to block the electromagnetic field generated by the magnet (130. described later) and the mover (200), and improves a driving efficiency of the mover (200) by causing the electromagnetic field not facing the mover (200) among the electromagnetic field generated by the magnet (130) to face the mover (200).

    [0038] The yoke upper plate (122) may take the shape of a square plate, when seen on a plane, and may be centrally formed with an opening for exposing a lens (described later) of the mover (200). The yoke lateral plate (124) may be extended from an edge of the yoke upper plate (122) to form a space for accommodating the magnet (130) by way of the yoke lateral plate (124) and the yoke upper plate (122).

    [0039] A plurality of magnets (130) may be fixed on an inner lateral surface of the yoke lateral plate (124) to generate the first electromagnetic field for driving the mover (200). The mover (200) may include a bobbin (210) and a coil block (220), and be fixed therein by a lens barrel and a lens (230). The mover (200) moves relative to the stator (100) to adjust a gap between an image sensor arranged underneath the base (300. described later) and the lens (230).

    [0040] The bobbin (210) may take the shape of a cylinder formed with a hollow hole, for example, and be formed therein with a thread for fixing the lens (230). The bobbin (210) may be formed at a bottom periphery with a sill (213) for fixing the coil block (220. described later).

    [0041] The coil block (220) may be fixed at a periphery of the bobbin (210).

    [0042] The coil block (220) may be formed by directly winding a wire insulated by enamel resin on a periphery of the bobbin (210), or by winding a wire in a cylindrical shape and bonding the wound wire on the periphery of the bobbin (210) using an adhesive.

    [0043] The coil block (220) may generate a second electromagnetic field by way of a current applied from outside, and an attractive force and a repulsive force may be generated between the mover (200) and the stator (100) by a direction of a current applied to the coil block (220).

    [0044] The base (300) may take the shape of a plate to fix the stator (100), and may be centrally formed with an opening (310) through which light having passed the lens (230) embedded in the bobbin (210) of the mover (200).

    [0045] Each of four corners on an upper surface of the plate-shaped base (300) may be formed with a coupling pillar (320), and the coupling pillar (320) may function to couple a can (described later) to the base (300). The base (300) may be fixed at a rear surface thereof with an image sensor that generates an image corresponding to the light that has passed the lens (230). A frame-shaped spacer (330) may be arranged between the base (300) and the magnet (130) of the stator (100).

    [0046] The elastic member (400) may include a first elastic member (410) and a second elastic member (420). The elastic member (400) may elastically support the bobbin (210) of the mover (200). The elastic member (400) may form a gap (G) between a bottom surface (212) of the bobbin (210) and an upper surface (301) of the base (300) when no current is applied to the coil (220).

    [0047] In the exemplary embodiment of the present invention, in a case the mover (200) is distanced from the upper surface (301) of the base (300) when no current is applied to the coil using the elastic member (400), the mover (200) may be driven either to a downward direction facing the base (300) or to an upward direction distancing from the base (300) according to changed current direction.

    [0048] That is, in a case the mover (200) is distanced from the upper surface (301) of the base (300) using the elastic member (400) when no current is applied to the coil (220), the mover (200) may be driven either to a downward direction or to an upward direction in a still state.

    [0049] The first elastic member (410) may be elastically coupled to the bottom surface (212) of the bobbin (210) facing the base (300). Two first elastic members (410) may be formed, each member being elastically insulated from the other. Any one first elastic member (410) may be electrically connected to a distal end of the wire forming the coil block (220), and the other first elastic member (410) may be electrically connected to the other distal end facing the distal end of the wire.

    [0050] Now, referring to FIG.2, each of the first elastic members (410) may commonly include an inner elastic unit (412), an outer elastic unit (414) and a connection elastic unit (416).

    [0051] The inner elastic unit (412) may be coupled to the bottom surface (212) of the bobbin (210), the outer elastic unit (414) may be coupled by the spacer (330) and the connection elastic unit (416) may elastically connect the inner elastic unit (412) and the outer elastic unit (414). The connection elastic unit (416) may be formed by bending the thin narrow-width linear type elastic member, when viewed on a plane.

    [0052] Each of the outer elastic unit (414) of the first elastic members (410) may be partially protruded, and the protruded portion is bent along a lateral surface of the base (300) to be electrically connected to an outside circuit substrate. A current is applied to each outer elastic unit (414) of the first elastic members from the outside circuit substrate, and the current provided to the each outer elastic unit (414) is provided to the coil block (220), whereby the second electromagnetic field for ascending/descending the mover (200) is generated from the coil block (220).

    [0053] The second elastic member (420) may be elastically coupled to the upper surface (214) facing the bottom surface (212) of the bobbin (210) facing the base (300). The second elastic member (420) may include an inner elastic unit (422), an outer elastic unit (424) and a connection elastic unit (426).

    [0054] The inner elastic unit (422) may be coupled to the upper surface (214) facing the bottom surface (212) of the bobbin (210), the outer elastic unit (424) may be arranged on the yoke upper plate (122) of the yoke (120), and the connection elastic unit (426) may be connected to the inner and outer elastic units (422, 424).

    [0055] In the present exemplary embodiment, the inner elastic unit (412) of the first elastic member (410) connected to the mover (200) and the inner elastic unit (422) of the second elastic member (420) are arranged at a place lower than that of the outer elastic unit (414) because of a self weight of the mover (200) and gravity.

    [0056] As a result, the gap (G) formed between the bottom surface (212) of the bobbin (210) and an upper surface (301) of the base (300) is preferably set up in consideration of droop of the inner elastic unit (422) caused by the self weight of the mover (200) and gravity.

    [0057] In another exemplary embodiment, the connection elastic members (416, 426) may be deformed to allow the inner elastic units (412, 422) of the first and second elastic members (410, 420) to be formed at a position higher than that of the outer elastic units (414, 424), thereby preventing the mover (200) from drooping due to self weight of the mover (200) and the gravity.

    [0058] In a case the inner elastic units (412, 422) of the first and second elastic members (410, 420) are placed on a high position than the outer elastic units (414, 424) in consideration of the droop of the mover (200) by self weight of the mover (200) and the gravity, the first and second elastic members (410, 420) may be arranged in parallel with the upper surface (301) of the base (300).

    [0059] Referring back to FIG.1, the voice coil motor (600) may further include a cover can (500).

    [0060] The cover can (500) may include an upper plate (510) formed with an opening for exposing the lens (230) of the mover (200) and formed in the shape of a plate corresponding to the base (300), and a lateral plate (520) extended from an edge of the upper plate (510) to the base (300), where the lateral plate (520) is coupled to the lateral surface of the base (300).

    [0061] Referring back to FIG.1, the mover (200) according to an exemplary embodiment of the present invention may be driven to either a first direction facing the base (300) or a second direction opposite to the first direction. Therefore, the mover (200) may collide with the base (300) or the upper plate (510) of the cover can (500) while being driven to the first direction or to the second direction, whereby noise can be generated due to deformation of the first and second elastic members (410, 420) or collision. Therefore, the voice coil motor (600) may further include a first shock absorption member (340) and a second shock absorption member (350) in order to prevent generation of noise.

    [0062] The first shock absorption member (340) may be formed on the upper surface (301) of the base (300) facing the bottom surface (212) of the bobbin (210), and the second shock absorption member (350) may be arranged at an inner lateral surface of the cover can (500) facing the upper surface (214) of the bobbin (210). The first shock absorption member (340) and the second shock absorption member (350) may include any one of a sponge, a synthetic resin having elasticity and a rubber.

    [0063] FIG. 3 is a cross-sectional view of a conventional voice coil motor for comparing with the voice coil motor according to an exemplary embodiment of the present invention, and FIG.4 is a graph illustrating a relation between an amount of driving current for driving the voice coil motor of FIG. 3 and movement.

    [0064] Referring to FIGS. 3 and 4, a bobbin of a conventional voice coil motor (10) and a mover (2) including a coil block are elastically coupled to a stator (1) by an elastic member (3), and the mover (2) is arranged on a base (4) by the elastic member (3) generating elasticity pressing the mover (2) in a direction facing the base (4).

    [0065] FIG.3 shows a mover (2) that is not applied with a driving current for driving the mover (2).

    [0066] A current is applied to the coil block of the mover (2) for adjusting a focus between an image sensor and the mover (2) by widening a gap between the image sensor arranged underneath the base (4) and a lens included in the mover (2), whereby an electromagnetic field is generated by the coil block.

    [0067] The electromagnetic field generated by the coil block reacts with the electromagnetic generated by a magnet of the stator (1) to generate an ascending force to a direction facing an upper surface of the base (4). The ascending force increases in proportion to the intensity of the current applied to the coil block.

    [0068] Referring to FIGS. 3 and 4, the mover (2) of the conventional voice coil motor (10) is not distanced from the base (4) until a current applied to the coil block by the elasticity depressing the mover (2) downward according to a self weight of the mover (2) and gravity reaches a point of start current of a horizontal axis in the graph of FIG.4.

    [0069] As shown in the graph of FIG.4, in a case the current applied to the coil block is greater than the start current, the ascending force applied to the mover (2) becomes greater than the self weight of the mover (2) and the elasticity of the elastic member (3), whereby the mover (2) is distanced from the base (4) of the mover (2).

    [0070] Successively, the current applied to the coil block continuously increases to keep increasing a gap between the mover (2) and the base (4) until the current reaches a B point in the graph of FIG.4.

    [0071] Meanwhile, the elasticity of elastic member (3) also increases as the gap between the mover (2) and the base (4) continuously increases, whereby the mover (2) is distanced from an upper surface of the base (4) as much as A at a particular current (B). For example, in a case a current of approximately 80mA is provided to the coil block, the mover (2) stops short of ascending further from a particular position.

    [0072] FIG.5 is a schematic cross-sectional view of a voice coil motor according to an exemplary embodiment of the present invention, and FIG.6 is a graph illustrating a relation between a driving current for driving a voice coil motor and a movement.

    [0073] Referring to FIGS. 1, 5 and 6, the mover (20) including a bobbin (210) and a coil block (220) is elastically coupled to the stator (100) by the first and second elastic members (410, 420) of the elastic member (400), and the mover (200) is distanced from the upper surface of the base (400) in a case a current is not applied to the b coil block (220) by the elasticity of the first and second elastic members (410, 420).

    [0074] The coil block (220) of the mover (200) is applied with a current of forward direction, for example, in order to widen a gap between the image sensor arranged underneath the base (400) and the lens included in the mover (200), whereby a first electromagnetic field is generated from the coil block (220). The first electromagnetic field generated from the coil block (220) reacts with the electromagnetic generated by a magnet (130) of the stator (100) to generate an ascending force to a direction facing an upper surface of the base (400). The ascending force increases in proportion to the intensity of the forward current applied to the coil block (220).

    [0075] As depicted in FIGS. 5 and 6, the elastic members (410, 420) of the voice coil motor (600) according to the exemplary embodiment of the present invention do not depress the mover (200) to a direction facing the base (300) when a current is not applied to the mover (200), such that, upon application of forward current to the coil block (220), the mover (200) starts to ascend to a first direction distancing from the upper surface of the base (300).

    [0076] Now, a current in an area where Y axis becomes a positive number in the graph of FIG. 6 is defined as a "forward current", while a current in an area where Y axis becomes a negative number in the graph of FIG. 6 is defined as a "backward current".

    [0077] Furthermore, because the mover (200) of the voice coil motor (600) according to the exemplary embodiment of the present invention has been already distanced from the base before the forward current is applied to the mover (200), even a small amount of current of an approximately 25mA (approximately 1/3 of 80mA necessary for reaching the A point in the conventional voice coil motor illustrated in FIG.4) is sufficient enough to reach the A point.

    [0078] That is, in the exemplary embodiment of the present invention, even a small amount of current can ascend the mover (200) to a desired position, because the mover (200) is already in a position distanced from the upper surface of the base (300) before the current is applied to the coil block (220), using the first and second elastic members (410, 420).

    [0079] Meanwhile, a current of backward direction (instead of forward direction) is applied to the coil block (220) in order to drive the mover (200) of the voice coil motor (600) according to the exemplary embodiment of the present invention to a second direction approaching the base (300).

    [0080] A descending force is generated on the coil block (220) by the electromagnetic field generated by the backward current applied to the coil block (220) and the electromagnetic field generated by the magnet (130), and the mover (200) is moved to a direction facing the upper surface (301) of the base (300) by the descending force to allow the mover (200) to be arranged on the upper surface (301) of the base (300).

    [0081] FIG.7 is a block diagram illustrating a driving circuit for ascending or descending a mover of a voice coil motor according to an exemplary embodiment of the present invention.

    [0082] Referring to FIGS. 1 and 7, the mover (200) is distanced from the upper surface (301) of the base (300) by the first and second elastic members (410, 420) when no current is applied to the coil block (220) of the mover (200), and the mover (200) is driven to a first direction facing the upper surface (301) of the base (300) or a second direction opposite to the first direction by the current applied to the coil block (220) of the mover (200) distanced from the upper surface (301) of the base (300).

    [0083] A voice coil motor (800) may include a driving module (700) for changing the flow of current applied to the coil block (220) in order to drive the mover (200) to any one direction of the first direction and the second direction. The driving module (700) may include a control unit (710) and a current providing unit (790).

    [0084] The control unit (710) is electrically connected to an outside circuit substrate to generate an ascending control signal (S1) and a descending control signal (S2).

    [0085] The ascending control signal (S1) is a control signal for increasing the gap between the bobbin (210) of the voice coil motor and the upper surface (301) of the base (300), and the descending control signal (S2) is a control signal for decreasing the gap between the bobbin (210) of the voice coil motor and the upper surface (301) of the base (300).

    [0086] The current providing unit (790) provides to the coil block (220) a current of forward direction" for increasing the gap between the mover (200) and the upper surface (301) of the base (300) in response to the ascending control signal (S1), and the current providing unit (790) also provides to the coil block (220) a current of backward direction" for decreasing the gap between the mover (200) and the upper surface (301) of the base (300) in response to the descending control signal (S2).

    [0087] The current providing unit (790) may include a power source (715), a first unit circuitry (720) and a second unit circuitry (730).

    [0088] The first unit circuitry (720) may include first and second switch elements (Q1, Q2). In the exemplary embodiment of the present invention, the first and second switch elements (Q1, Q2) may be respectively transistors including input terminals, output terminals and gates. The output terminal of the first switch element (Q1) is connected to the output terminal of the second switch terminal (Q2).

    [0089] The second unit circuitry (730) may include third and fourth switch elements (Q3, Q4). In the exemplary embodiment of the present invention, the third and fourth switch elements (Q3, Q4) may be respectively transistors including input terminals, output terminals and gates. The output terminal of the third switch element (Q3) is connected to the output terminal of the fourth switch terminal (Q4).

    [0090] In the exemplary embodiment of the present invention, the first and second switch elements (Q1, Q2) are connected to the power source (715) in parallel. That is, input terminals of the first and second switch elements (Q1, Q2) at the first unit circuitry (720) and the input terminals of the third and fourth switch elements (Q3, Q4) at the second unit circuitry (730) are respectively inputted by a current provided from the power source (715).

    [0091] Meanwhile, output terminals of the first and second switch elements (Q1, Q2) at the first unit circuitry (720) and the output terminals of the third and fourth switch elements (Q3, Q4) at the second unit circuitry (730) are respectively and electrically connected to one distal end of a line comprising the coil block (220) and the other end facing the one distal end.

    [0092] In terms of operation, the ascending control signal (S1) outputted from the control unit (710) is applied to a gate of the first switch element (Q1) and to a gate of the fourth switch element (Q4). The descending control signal (S2) outputted from the control unit (710) is electrically connected to a gate of the second switch element (Q2) and to a gate of the third switch element (Q3).

    [0093] Therefore, as illustrated in FIG. 8, in a case the ascending control signal (S1) is outputted from the control unit (710), the ascending control signal (S1) is also applied to the gate of the first switch element (Q1) and the gate of the fourth switch element (Q4). That is, the first switch element (Q1), the coil block (220), the fourth switch element (Q4) and the power source (715) form a closed circuit to thereby apply a "current of forward direction" to the coil block (220).

    [0094] The gap between the mover (200) of the voice coil motor (700) and the upper surface (301) of the base (300) increases as the current of forward direction is applied to the coil block (220).

    [0095] Meanwhile, as illustrated in FIG.9, in a case the descending control signal (S2) is outputted from the control unit (710), each gate of the first and second switch elements (Q1, Q2) is also applied with the descending control signal (S2). As a result, the third switch element (Q3), the coil block (220), the second switch element (Q2) and the power source (715) form a closed circuit to thereby apply a "current of backward direction" to the coil block (220) that is opposite to the current of forward direction. In a case a "current of backward direction" is applied to the coil block (220), the gap between the mover (200) of the voice coil motor (700) and the upper surface (301) of the base (300) decreases.

    [0096] In the present exemplary embodiment of the present invention, although a configuration is explained and illustrated in which four switch elements (Q1, Q2, Q3, Q4) are used to variably control the directions of current flowing in the coil block (220), the directions of current flowing in the coil block (220) may be changed using various other electrical elements.

    [0097] In the present exemplary embodiment of the present invention, although a configuration is explained and illustrated in which four switch elements (Q1, Q2, Q3, Q4) are used to variably control the directions of current flowing in the coil block (220), a voltage difference across the coil block (220) may be adjusted to ascend or descend the bobbin (210) by applying a voltage across the coil block (220).

    [Mode for Invention]



    [0098] Now, a method for driving a voice coil motor according to an exemplary embodiment of the present invention will be described.

    [0099] Referring to FIGS. 1 and 10, the current of backward direction (FC) is applied to the coil block (220) to move the bobbin (210) to the reference position, where the coil block (220) is arranged at a place distanced from the upper surface (301) of the base (300) fixed by the magnet (130) of the voice coil motor (700), elastically supported by elastic member (400) including first and second elastic members (410, 420), and embedded with the lens (230).

    [0100] The reference position in the exemplary embodiment of the present invention may be the upper surface (301) of the base (300).

    [0101] Successively, the current of backward direction (FC) is increased on the coil block (220) to distance the bobbin (210) from the reference position, and if the bobbin (210) reaches an initial position (S), a current of forward direction (SC) is applied. The current of forward direction (SC) may increase continuously or in a stair formation.

    [0102] Thereafter, the current of forward direction (SC) is maintained at a constant level when an optimum focus that is required by a lens (230) fixed at the bobbin (210) and the image sensor module is formed, to thereby stop the bobbin (210) at a position corresponding to that of the optimum focus.

    [0103] Using the process of stopping the bobbin (210) at a position corresponding to the optimum focus, a process of moving the bobbin (210) to a place a bit deviated from the position of the optimum focus and a process of a bit decreasing the current of forward direction to the coil block (220), the bobbin (210) can be returned to a position of the optimum focus, whereby a fine focusing process is performed to minutely adjust a focus between the lens (230) of the bobbin (210) and the image sensor module.

    [0104] Successively, an object and the optimum focus are formed between the image sensor module and the lens (230), where the image sensor module generates an image of the object.

    [0105] Meanwhile, referring to FIGS. 1 and 11, the current of forward direction (SC) is applied to the coil block (220) to move the bobbin (210) to the reference position, where the coil block (220) is arranged at a place distanced from the upper surface (301) of the base (300) fixed by the magnet (130) of the voice coil motor (700), elastically supported by elastic member (400) including first and second elastic members (410, 420), and embedded with the lens (230).

    [0106] The reference position in the exemplary embodiment of the present invention may be an inner lateral surface of the upper surface (501) of the cover can (510).

    [0107] Successively, the current of forward direction (SC) is decreased on the coil block (220) to distance the bobbin (210) from the upper plate (510) of cover can (510) which is the reference position, and if the bobbin (210) reaches an initial position (S), a current of backward direction (FC) is applied. The current of backward direction (FC) may increase continuously or in a stair formation.

    [0108] Thereafter, the current of backward direction (FC) is maintained at a constant level when an optimum focus that is required by a lens (230) fixed at the bobbin (210) and the image sensor module is formed, to thereby stop the bobbin (210) at a position corresponding to that of the optimum focus.

    [0109] Using the process of stopping the bobbin (210) at a position corresponding to the optimum focus, a process of moving the bobbin (210) to a place a bit deviated from the position of the optimum focus and a process of a bit increasing the current of backward direction (SC) to the coil block (220), the bobbin (210) can be returned to a position of the optimum focus, whereby a fine focusing process is performed to minutely adjust a focus between the lens (230) of the bobbin (210) and the image sensor module.

    [0110] Successively, an object and the optimum focus are formed between the image sensor module and the lens (230), where the image sensor module generates an image of the object.

    [0111] Although the method for driving the voice coil motor according to exemplary embodiment of the present invention has described a method in which the bobbin (210) is brought into contact with any one of the upper surface (301) of the base (300) or an inner lateral surface of the upper plate (510) of the cover can (500) to set up a reference position, and a current is applied to the coil block (220) until the bobbin (210) reaches a position formed by the image sensor module and the optimum focus from the reference position to thereby adjust a focus between the mover (200) and the image sensor module, another method may be alternatively applied in which the bobbin (210) is moved to a reference position by applying a first current to the coil block (220) that is elastically supported at a place distanced from the upper surface (301) of the base fixed by the magnet (130), and embedded with the lens (230), a data is calculated for maintaining an optimum focus between the lens (230) and the image sensor module based on the object, and an amount of current corresponding to the data is applied to the coil block (220) to move the bobbin (210) to the reference position based on the data.

    [0112] At this time, the amount of current may have the intensity corresponding to the data, and the reference position may be the inner lateral surface of the upper plate (510) or the upper surface (301) of the base (300).

    [Industrial Applicability]



    [0113] As apparent from the foregoing, the present invention has an industrial applicability in that a bobbin mounted with a lens is distanced from an upper surface of a base mounted with an image sensor, and a current of forward direction or backward direction is applied to a coil block wound on the bobbin to drive the mover including the bobbin to a direction distancing from the base or approaching the base, whereby power consumption by the voice coil motor can be reduced to adjust a focus between the lens and the image sensor within a faster period of time and to reduce a contact noise caused by driving of the bobbin.

    [0114] While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, the general inventive concept is not limited to the above-described embodiments. It will be understood by those of ordinary skill in the art that various changes and variations in form and details may be made therein within the scope of the appended claims.


    Claims

    1. A camera comprising a VCM, i.e. a Voice Coil Motor, a lens and an image sensor, wherein the VCM comprises:

    a base (300) formed with an opening;

    a mover (200) including a bobbin (210) formed with a hollow hole and a coil block (220) disposed on a periphery of the bobbin (210);

    a magnet (130) configured to interact with the coil block (220);

    an elastic member (400) including a first elastic member (410) coupled to a lower portion of the bobbin (210) and a second elastic member (420) coupled to a upper portion of the bobbin (210); and

    a cover can (500) including an upper plate (510) being centrally formed with an opening and a lateral plate (520) being extended from an edge of the upper plate (510) toward the base (300),

    characterized in that

    each of the first and second elastic members (410, 420) comprises an inner elastic unit (412, 422) coupled to the bobbin (210), an outer elastic unit (414, 424), and a connection elastic unit (416, 426) connecting the inner and outer elastic units (412, 422, 414, 424),

    the elastic member (400) is configured to support the bobbin (210) and to form a first gap between the bobbin (210) and the base (300) and a second gap between the bobbin (210) and the cover can(500) at an initial position where a current for driving the VCM is not applied to the coil block (220),

    the inner elastic unit (412) of the first elastic member (410) is disposed at a position lower than the outer elastic unit (414) of the first elastic member (410) at the initial position,

    the inner elastic unit (422) of the second elastic member (420) is disposed at a position lower than the outer elastic unit (424) of the second elastic member (420) at the initial position, and

    the mover (200) is stationary and distanced from both the base (300) and the cover can (500) at the initial position, and

    the mover (200) is configured to be driven along an optical axis downwardly to decrease the first gap from the initial position when a backward current is applied to the coil block (220), and the mover (200) is configured to be driven along the optical axis upwardly to decrease the second gap from the initial position when a forward current is applied to the coil block (220),

    wherein the VCM is adapted to move the mover (200) downwardly from the initial position to a reference position by applying the backward current to the coil block (220), and to move the mover (220) upwardly from the reference position toward the initial position by reducing the backward current applied to the coil block (220), and to move the mover (220) upwardly by applying the forward current to the coil block (220),

    and to stop the mover at a position of an optimum focus by moving the mover (220) to a position deviated from the position of the optimum focus and then by returning the bobbin to the position of the optimum focus by decreasing the forward current.


     
    2. The camera of claim 1, wherein the VCM is adapted to further perform a fine focusing process to stop the mover at the position of the optimum focus.
     
    3. The camera of claim 1 or 2, wherein the lateral plate (520) of the cover can (500) is coupled to the base (300).
     
    4. The camera of any one of claims 1 to 3, wherein the first elastic member (410) comprises two elastic members, separated from each other, wherein one of said two elastic members is electrically connected to a first end of the coil block (220), and the other of said two elastic members is electrically connected to a second end of the coil block (220), and wherein the current for driving the VCM is configured to be applied to the coil block (220) through the two elastic members of the first elastic member (410).
     
    5. The camera of any one of claims 1 to 4, wherein the outer elastic unit (424) of the second elastic member (420) is disposed in the cover can (500).
     
    6. The camera of any one of claims 1 to 5, wherein the bobbin (210) is configured to make contact with the base (300) downwardly and the upper plate (510) of the cover can (500) upwardly and wherein the mover (200) is configured to move between the base (300) and the cover can (500).
     
    7. The camera of any one of claims 1 to 6, wherein the inner elastic units (412, 422) of the first and second elastic member (410, 420) are configured to move by extension of the connection elastic units (416, 426) while the outer elastic units (414, 424) are fixed.
     
    8. The camera of any one of claims 1 to 7, wherein the bobbin (210) comprises a thread for fixing the lens (230), and wherein the bobbin (210) comprises a sill (213) for supporting the coil block (220) at the periphery of the bobbin (210).
     
    9. The camera of any one of claims 1 to 8, further comprising a first shock absorption member (340) disposed on an upper surface of the base (300) and facing the lower portion of the bobbin (210), and a second shock absorption member (350) disposed on an inner surface of the upper plate (510) of the cover can (500) and facing the upper portion of the bobbin (210).
     
    10. The camera of claim 6, wherein the mover (200) is configured to move between a first position with a first value of the forward current where the bobbin (210) contacts the cover can (500) and not in contact with the base (300) when the forward current is applied to the coil block and a second position with a second value of the backward current where the bobbin (210) contacts the base (300) and not in contact with the cover can (500) when the backward current is applied to the coil block (220).
     
    11. The camera of claim 10, wherein the mover (200) does not move upwardly at the first position when the forward current applied to the coil block (220) increases more than the first value of the forward current, and wherein the mover (200) does not move downwardly at the second position when the backward current applied to the coil block (220) increases more than the second value of the backward current.
     
    12. The camera of claim 10 or 11, wherein a position of the mover (200) between the first position and the second position has linearity with respect to an amount of change of the current for driving the VCM.
     
    13. The camera of any one of claims 10 to 12, wherein the mover (200) is configured to move between the first position and the second position by adjusting a voltage difference between opposite ends of the coil block (220).
     
    14. The camera of any one of claims 1 to 13, further comprising a driving module (700), wherein the driving module (700) comprises a control unit (710) suitable to generate an ascending control signal for ascending the bobbin (210) and a descending control signal for descending the bobbin (210), and a current providing unit (790) providing either the forward current or the backward current to the coil block (220) in response to the ascending control signal and the descending control signal of the control unit (710).
     
    15. A mobile phone comprising the camera of any one of claims 1 to 14.
     


    Ansprüche

    1. Kamera umfassend einen VCM, d.h. einen Schwingspulenmotor (voice coil motor), eine Linse und einen Bildsensor,
    wobei der VCM umfasst:

    eine Basis (300), die mit einer Öffnung gebildet ist;

    eine Bewegungseinrichtung (200) umfassend einen Spulenkörper (210), der mit einem hohlen Loch gebildet ist, und einen Spulenblock (220), der am Umfang des Spulenkörpers (210) angeordnet ist;

    einen Magneten (130), der dazu konfiguriert ist, mit dem Spulenblock (220) zusammenzuwirken;

    ein elastisches Element (400) umfassend ein erstes elastisches Element (410), das mit einem unteren Abschnitt des Spulenkörpers (210) gekoppelt ist, und ein zweites elastisches Element (420), das mit einem oberen Abschnitt des Spulenkörpers (210) gekoppelt ist; und

    eine Abdeckungshülse (500) umfassend eine obere Platte (510), die zentral mit einer Öffnung gebildet ist, und eine seitliche Platte (520), die von einer Kante der oberen Platte (510) in Richtung der Basis (300) erstreckt ist,

    dadurch gekennzeichnet, dass

    jedes des ersten und des zweiten elastischen Elements (410, 420) eine innere elastische Einheit (412, 422), die mit dem Spulenkörper (210) gekoppelt ist, eine äußere elastische Einheit (414, 424) und eine elastische Verbindungseinheit (416, 426) umfasst, die die inneren und die äußeren elastischen Einheiten (412, 422, 414, 424) verbindet,

    das elastische Element (400) dazu konfiguriert ist, den Spulenkörper (210) zu tragen und einen ersten Spalt zwischen dem Spulenkörper (210) und der Basis (300) und einen zweiten Spalt zwischen dem Spulenkörper (210) und der Abdeckungshülse (500) an einer Anfangsposition zu bilden, wo ein Strom zum Antreiben des VCM nicht an den Spulenblock (220) angelegt ist,

    die innere elastische Einheit (412) des ersten elastischen Elements (410) an einer Position angeordnet ist, die niedriger als die äußere elastische Einheit (414) des ersten elastischen Elements (410) an der Anfangsposition ist,

    die innere elastische Einheit (422) des zweiten elastischen Elements (420) an einer Position angeordnet ist, die niedriger als die äußere elastische Einheit (424) des zweiten elastischen Elements (420) an der Anfangsposition ist, und

    die Bewegungseinrichtung (200) stationär und sowohl von der Basis (300) als auch der Abdeckungshülse (500) an der Anfangsposition beabstandet ist, und

    die Bewegungseinrichtung (200) dazu konfiguriert ist, entlang einer optischen Achse nach unten angetrieben zu werden, um den ersten Spalt von der Anfangsposition zu verringern, wenn ein Rückwärtsstrom an dem Spulenblock (220) angelegt ist, und die Bewegungseinrichtung (200) dazu konfiguriert ist, entlang der optischen Achse nach oben angetrieben zu werden, um den zweiten Spalt von der Anfangsposition zu verringern, wenn ein Vorwärtsstrom an den Spulenblock (220) angelegt ist,

    wobei der VCM daran angepasst ist, die Bewegungseinrichtung (200) durch Anlegen des Rückwärtsstroms an den Spulenblock (220) von der Anfangsposition nach unten zu einer Referenzposition zu bewegen, und die Bewegungseinrichtung (200) durch Reduzieren des an den Spulenblock (220) angelegten Rückwärtsstroms von der Referenzposition in Richtung der Anfangsposition nach oben zu bewegen, und die Bewegungseinrichtung (200) durch Anlegen des Vorwärtsstroms an den Spulenblock (220) nach oben zu bewegen,

    und die Bewegungseinrichtung an einer Position eines optimalen Fokus anzuhalten, indem die Bewegungseinrichtung (200) zu einer Position bewegt wird, die von der Position des optimalen Fokus abweicht, und indem dann der Spulenkörper zu der Position des optimalen Fokus zurückgebracht wird, indem der Vorwärtsstrom verringert wird.


     
    2. Kamera nach Anspruch 1, wobei der VCM daran angepasst ist, ferner einen Feinfokussierungsvorgang durchzuführen, um die Bewegungseinrichtung an der Position des optimalen Fokus anzuhalten.
     
    3. Kamera nach Anspruch 1 oder 2, wobei die seitliche Platte (520) der Abdeckungshülse (500) mit der Basis (300) gekoppelt ist.
     
    4. Kamera nach einem der Ansprüche 1 bis 3, wobei das erste elastische Element (410) zwei elastische Elemente umfasst, die voneinander getrennt sind, wobei eines der zwei elastischen Elemente mit einem ersten Ende des Spulenblocks (220) elektrisch verbunden ist, und das andere der zwei elastischen Elemente mit einem zweiten Ende des Spulenblocks (220) elektrisch verbunden ist, und wobei der Strom zum Antreiben des VCM dazu konfiguriert ist, durch die zwei elastischen Elemente des ersten elastischen Elements (410) an den Spulenblock (220) angelegt zu werden.
     
    5. Kamera nach einem der Ansprüche 1 bis 4, wobei die äußere elastische Einheit (424) des zweiten elastischen Elements (420) in der Abdeckungshülse (500) angeordnet ist.
     
    6. Kamera nach einem der Ansprüche 1 bis 5, wobei der Spulenkörper (210) dazu konfiguriert ist, mit der Basis (300) nach unten und der oberen Platte (510) der Abdeckungshülse (500) nach oben in Kontakt zu kommen, und wobei die Bewegungseinrichtung (200) dazu konfiguriert ist, sich zwischen der Basis (300) und der Abdeckungshülse (500) zu bewegen.
     
    7. Kamera nach einem der Ansprüche 1 bis 6, wobei die inneren elastischen Einheiten (412, 422) des ersten und des zweiten elastischen Elements (410, 420) dazu konfiguriert sind, sich durch Erstreckung der elastischen Verbindungseinheiten (416, 426) zu bewegen, während die äußeren elastischen Einheiten (414, 424) fixiert sind.
     
    8. Kamera nach einem der Ansprüche 1 bis 7, wobei der Spulenkörper (210) ein Gewinde zum Fixieren der Linse (230) umfasst, und wobei der Spulenkörper (210) einen Absatz (213) zum Tragen des Spulenblocks (220) am Umfang des Spulenkörpers (210) umfasst.
     
    9. Kamera nach einem der Ansprüche 1 bis 8, ferner umfassend ein erstes Stoßdämpfungselement (340), das an einer oberen Oberfläche der Basis (300) angeordnet und dem unteren Abschnitt des Spulenkörpers (210) zugewandt ist, und ein zweites Stoßdämpfungselement (350), das an einer inneren Oberfläche der oberen Platte (510) der Abdeckungshülse (500) angeordnet und dem oberen Abschnitt des Spulenkörpers (210) zugewandt ist.
     
    10. Kamera nach Anspruch 6, wobei die Bewegungseinrichtung (200) dazu konfiguriert ist, sich zwischen einer ersten Position mit einem ersten Wert des Vorwärtsstroms, wo der Spulenkörper (210) die Abdeckungshülse (500) kontaktiert und nicht in Kontakt mit der Basis (300) ist, wenn der Vorwärtsstrom an den Spulenblock angelegt ist, und einer zweiten Position mit einem zweiten Wert des Rückwärtsstroms zu bewegen, wo der Spulenkörper (210) die Basis (300) kontaktiert und nicht in Kontakt mit der Abdeckungshülse (500) ist, wenn der Rückwärtsstrom an den Spulenblock (220) angelegt ist.
     
    11. Kamera nach Anspruch 10, wobei sich die Bewegungseinrichtung (200) an der ersten Position nicht nach oben bewegt, wenn der an den Spulenblock (220) angelegte Vorwärtsstrom mehr als auf den ersten Wert des Vorwärtsstrom ansteigt, und wobei die Bewegungseinrichtung (200) sich an der zweiten Position nicht nach unten bewegt, wenn der an den Spulenblock (220) angelegte Rückwärtsstrom mehr als auf den zweiten Wert des Rückwärtsstroms ansteigt.
     
    12. Kamera nach Anspruch 10 oder 11, wobei eine Position der Bewegungseinrichtung (200) zwischen der ersten Position und der zweiten Position eine Linearität bezüglich eines Änderungsbetrags des Stroms zum Antreiben des VCM aufweist.
     
    13. Kamera nach einem der Ansprüche 10 bis 12, wobei die Bewegungseinrichtung (200) dazu konfiguriert ist, sich durch Anpassen eines Spannungsunterschieds zwischen gegenüberliegenden Enden des Spulenblocks (220) zwischen der ersten Position und der zweiten Position zu bewegen.
     
    14. Kamera nach einem der Ansprüche 1 bis 13, ferner umfassend ein Antriebsmodul (700), wobei das Antriebsmodul (700) eine Steuereinheit (710), die geeignet ist, ein aufsteigendes Steuersignal zum Anheben des Spulenkörper (210) und ein absteigendes Steuersignal zum Absenken des Spulenkörpers (210) zu erzeugen, und eine Strombereitstellungseinheit (790) umfasst, die entweder den Vorwärtsstrom oder den Rückwärtsstrom für den Spulenblock (220) in Ansprechung auf das aufsteigende Steuersignal und das absteigende Steuersignal der Steuereinheit (710) bereitstellt.
     
    15. Mobiltelefon umfassend die Kamera nach einem der Ansprüche 1 bis 14.
     


    Revendications

    1. Un appareil de prise de vues comprenant un VCM, c'est-à-dire un moteur à bobine acoustique ("Voice Coil Motor"), un objectif et un capteur d'image, dans lequel le VCM comprend :

    une embase (300) formée avec une ouverture ;

    un organe de déplacement (200) comprenant une bobine (210) formée avec un trou creux et un bloc formant bobine (220) disposé sur une périphérie de la bobine (210) ;

    un aimant (130) configuré pour interagir avec le bloc formant bobine (220) ;

    un organe élastique (400) comprenant un premier organe élastique (410) relié à une partie inférieure de la bobine (210) et un deuxième organe élastique (420) relié à une partie supérieure de la bobine (210) ; et

    un boîtage formant couvercle (500) comprenant une plaque supérieure (510) présentant une ouverture en son centre et une plaque latérale (520) s'étendant depuis un bord de la plaque supérieure (510) vers l'embase (300),

    caractérisé en ce que

    chacun des premier et deuxième éléments élastiques (410, 420) comprend une unité élastique interne (412, 422) reliée à la bobine (210), une unité élastique externe (414, 424) et une unité élastique de liaison (416, 426) reliant les unités élastiques interne et externe (412, 422, 414, 424),

    l'organe élastique (400) est configuré pour supporter la bobine (210) et pour former un premier espace entre la bobine (210) et l'embase (300) et un deuxième espace entre la bobine (210) et le boîtage formant couvercle (500) dans une position initiale dans laquelle un courant pour entraîner le VCM n'est pas appliqué au bloc formant bobine (220),

    l'unité élastique interne (412) du premier organe élastique (410) est disposée dans une position inférieure à l'unité élastique externe (414) du premier organe élastique (410) dans la position initiale,

    l'unité élastique interne (422) du deuxième organe élastique (420) est disposée dans une position inférieure à l'unité élastique externe (424) du deuxième organe élastique (420) dans la position initiale, et

    l'organe de déplacement (200) est stationnaire et éloigné à la fois de l'embase (300) et du boîtage formant couvercle (500) dans la position initiale, et

    l'organe de déplacement (200) est configuré pour être entraîné vers le bas selon un axe optique pour diminuer le premier espace depuis la position initiale lorsqu'un courant inverse est appliqué au bloc formant bobine (220), et l'organe de déplacement (200) est configuré pour être entraîné vers le haut selon l'axe optique pour diminuer le deuxième espace depuis la position initiale lorsqu'un courant direct est appliqué au bloc formant bobine (220),

    le VCM étant adapté pour déplacer l'organe de déplacement (200) vers le bas depuis la position initiale jusqu'à une position de référence en appliquant le courant inverse au bloc formant bobine (220), et pour déplacer l'organe de déplacement (200) vers le haut depuis la position de référence jusqu'à la position initiale en réduisant le courant inverse appliqué au bloc formant bobine (220), et pour déplacer l'organe de déplacement (200) vers le haut en appliquant le courant direct au bloc formant bobine (220),

    et pour arrêter l'organe de déplacement à une position d'une mise au point optimale en déplaçant l'organe de déplacement (200) dans une position déviée à partir de la position de la mise au point optimale et ensuite en ramenant la bobine à la position de mise au point optimale en réduisant le courant direct.


     
    2. L'appareil de prise de vues selon la revendication 1, dans lequel le VCM est adapté pour effectuer en outre un processus de mise au point fine pour arrêter l'organe de déplacement à la position de la mise au point optimale.
     
    3. L'appareil de prise de vues selon la revendication 1 ou la revendication 2, dans lequel la plaque latérale (520) du boîtage formant couvercle (500) est reliée à l'embase (300).
     
    4. L'appareil de prise de vues selon l'une quelconque des revendications 1 à 3, dans lequel le premier organe élastique (410) comprend deux éléments élastiques, séparés l'un de l'autre, l'un desdits deux éléments élastiques étant connecté électriquement à une première extrémité du bloc formant bobine (220), et l'autre desdits deux éléments élastiques étant connecté électriquement à une deuxième extrémité du bloc formant bobine (220), et le courant pour entraîner le VCM étant configuré pour être appliqué au bloc formant bobine (220) via les deux éléments élastiques du premier organe élastique (410).
     
    5. L'appareil de prise de vues selon l'une quelconque des revendications 1 à 4, dans lequel l'unité élastique externe (424) du deuxième organe élastique (420) est disposée dans le boîtage formant couvercle (500).
     
    6. L'appareil de prise de vues selon l'une quelconque des revendications 1 à 5, dans lequel la bobine (210) est configurée pour venir en contact avec l'embase (300) vers le bas et avec la plaque supérieure (510) du boîtage formant couvercle (500) vers le haut, et l'organe de déplacement (200) est configuré pour se déplacer entre l'embase (300) et le boîtage formant couvercle (500).
     
    7. L'appareil de prise de vues selon l'une quelconque des revendications 1 à 6, dans lequel les unités élastiques internes (412, 422) du premier et du deuxième organes élastiques (410, 420) sont configurées pour se déplacer par extension des unités élastiques de liaison (416, 426) alors que les unités élastiques externes (414, 424) sont fixes.
     
    8. L'appareil de prise de vues selon l'une quelconque des revendications 1 à 7, dans lequel la bobine (210) comprend un fil pour fixer la lentille (230), et dans lequel la bobine (210) comprend un seuil (213) pour supporter le bloc formant bobine (220) à la périphérie de la bobine (210).
     
    9. L'appareil de prise de vues selon l'une quelconque des revendications 1 à 8, comprenant en outre un premier élément amortisseur (340) disposé sur une surface supérieure de l'embase (300) et tourné vers la partie inférieure de la bobine (210), et un deuxième élément amortisseur (350) disposé sur une surface intérieure de la plaque supérieure (510) du boîtage formant couvercle (500) et tourné vers la partie supérieure de la bobine (210).
     
    10. L'appareil de prise de vues selon la revendication 6, dans lequel l'organe de déplacement (200) est configuré pour se déplacer entre une première position avec une première valeur du courant direct dans laquelle la bobine (210) est en contact avec le boîtage formant couvercle (500) et n'est pas en contact avec l'embase (300) lorsque le courant direct est appliqué au bloc formant bobine et une deuxième position avec une deuxième valeur du courant inverse dans laquelle la bobine (210) est en contact avec l'embase (300) et n'est pas en contact avec le boîtage formant couvercle (500) lorsque le courant inverse est appliqué au bloc formant bobine (220).
     
    11. L'appareil de prise de vues selon la revendication 10, dans lequel l'organe de déplacement (200) ne se déplace pas vers le haut dans la première position lorsque le courant direct appliqué au bloc formant bobine (220) augmente plus que la première valeur du courant direct, et dans lequel l'organe de déplacement (200) ne se déplace pas vers le bas dans la deuxième position lorsque le courant inverse appliqué au bloc formant bobine (220) augmente davantage que la deuxième valeur du courant inverse.
     
    12. L'appareil de prise de vues selon la revendication 10 ou la revendication 11, dans lequel une position de l'organe de déplacement (200) entre la première position et la deuxième position a une linéarité par rapport à une quantité de variation du courant pour entraîner le VCM.
     
    13. L'appareil de prise de vues de l'une quelconque des revendications 10 à 12, dans lequel l'organe de déplacement (200) est configuré pour se déplacer entre la première position et la deuxième position en réglant une différence de tension entre des extrémités opposées du bloc formant bobine (220).
     
    14. L'appareil de prise de vues de l'une quelconque des revendications 1 à 13, comprenant en outre un module d'entraînement (700), le module d'entraînement (700) comprenant une unité de commande (710) appropriée pour générer un signal de commande de montée pour faire monter la bobine (210) et un signal de commande de descente pour faire descendre la bobine (210), et une unité (790) de fourniture de courant fournissant le courant direct ou le courant inverse au bloc formant bobine (220) en réponse au signal de commande de montée et au signal de commande de descente de l'unité de commande (710).
     
    15. Un téléphone mobile comprenant l'appareil de prise de vues de l'une quelconque des revendications 1 à 14.
     




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    Cited references

    REFERENCES CITED IN THE DESCRIPTION



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    Patent documents cited in the description