KR102322151B1 - Voice coil motor - Google Patents

Abstract

The voice coil motor includes a stator including a first driving unit; a mover disposed inside the stator and including a second driving unit reacting with the first driving unit and having a lens mounted therein; a base for fixing the stator; and an elastic member coupled to the mover to separate the mover from the base when a driving signal is not applied to the first or second driving unit, wherein the mover moves toward the base in a first direction or the It moves in a second direction away from the base, and the first stroke length of the mover in the first direction and the second stroke length of the mover in the second direction are different from each other.

Description

Voice coil motor {VOICE COIL MOTOR}

The present invention relates to a voice coil motor.

Recently, a mobile phone having a built-in ultra-small digital camera has been developed.

In the case of a miniature digital camera applied to a conventional mobile phone, etc., the distance between the image sensor and the lens that changes external light into a digital image or digital image could not be adjusted. With the development of the same lens driving device, it is possible to obtain an improved digital image or digital image from a miniature digital camera.

In general, the voice coil motor has a lens mounted therein, and a bobbin disposed on the base moves upward from the base to adjust the distance between the lens and the image sensor disposed on the rear side of the base.

In addition, a leaf spring is coupled to the bobbin of the voice coil motor, so that when the voice coil motor does not operate, the bobbin is always in contact with the upper surface of the base by the elastic force of the leaf spring. That is, the bobbin of the conventional voice coil motor is driven only in one direction with respect to the base.

Since the conventional voice coil motor is driven in only one direction, a driving force greater than the weight of the bobbin and the elastic force of the leaf spring is required to drive the voice coil motor, and thus power consumption of the voice coil motor is greatly increased.

In addition, since a driving force greater than the bobbin's own weight and the elastic force of the leaf spring is required to drive the voice coil motor, the size of the coil wound on the magnet or bobbin increases, thereby increasing the overall size of the voice coil motor.

(Patent Document 1) JP2008-281863 A

The present invention provides a voice coil motor that allows a mover to be floated from a base so that the mover can be driven in both directions with a smaller current, and power consumption can be further reduced when an infinite focusing area is used.

The technical problems to be achieved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by those of ordinary skill in the art to which the present invention belongs from the description below. will be.

In one embodiment, the voice coil motor includes a stator including a first driving unit; a mover disposed inside the stator and including a second driving unit reacting with the first driving unit and having a lens mounted therein; a base for fixing the stator; and an elastic member coupled to the mover to separate the mover from the base when a driving signal is not applied to the first or second driving unit, wherein the mover moves toward the base in a first direction or the It moves in a second direction away from the base, and the first stroke length of the mover in the first direction and the second stroke length of the mover in the second direction are different from each other.

In one embodiment, the voice coil motor includes a stator including a first driving unit; a mover disposed inside the stator and including a second driving unit reacting with the first driving unit and having a lens mounted therein; a base for fixing the stator; and an elastic member coupled to the mover to separate the mover from the base when a driving signal is not applied to the first or second driving unit, wherein the mover moves toward the base in a first direction or the A first central portion moving in a second direction away from the base and bisecting the upper and lower surfaces of the movable member and a second central portion bisecting the distance between the upper surface of the base and the inner surface of the cover facing the base are misaligned do.

According to the voice coil motor according to the present invention, when a driving signal is not applied, the mover floats from the upper surface of the base, and the stroke length or gap between the floating mover and the upper surface of the base is between the floating mover and the cover. By forming it differently from the stroke length or the gap, it is possible to realize low current or low power consumption characteristics.

1 is a cross-sectional view of a voice coil motor according to an embodiment of the present invention.
FIG. 2 is a graph illustrating current-distance characteristics of the voice coil motor of FIG. 1 .
3 is a cross-sectional view illustrating an inverted state of the voice coil motor of FIG. 1 .
4 is a cross-sectional view of a voice coil motor according to another embodiment of the present invention.

Hereinafter, an embodiment according to the present invention will be described in detail with reference to the accompanying drawings. In this process, the size or shape of the components shown in the drawings may be exaggerated for clarity and convenience of explanation. In addition, terms specifically defined in consideration of the configuration and operation of the present invention may vary depending on the intention or custom of the user or operator. Definitions of these terms should be interpreted as meanings and concepts consistent with the technical idea of the present invention based on the contents throughout this specification.

1 is a cross-sectional view of a voice coil motor according to an embodiment of the present invention. FIG. 2 is a graph illustrating current-distance characteristics of the voice coil motor of FIG. 1 .

1 and 2 , the voice coil motor 100 includes a base 110 , a stator 120 , a mover 130 , an elastic member 140 , and a cover 150 .

The base 110 is formed in a plate shape with an opening in the center, and the base 110 serves as a lower stopper of the mover 130 .

A receiving groove for accommodating the lower surface of the mover 130 may be formed on the upper surface of the base 110 to separate the lower surface of the mover 130 and the upper surface of the base 110 .

A shock absorbing member 115 is disposed on the upper surface of the base 110 to prevent the mover 130 and the base 110 from colliding and generating noise. The shock absorbing member 115 may include, for example, any one of a sponge, a synthetic resin having elasticity, and a rubber.

The stator 120 is fixed on the base 110 , and the stator 120 includes a first driving unit 125 for generating a magnetic field, and an accommodation space is formed inside the stator 120 .

In one embodiment of the present invention, the first driving unit 125 may include, for example, a coil formed by winding a long wire insulated by an insulating resin to generate a magnetic field by current. Alternatively, the first driving unit 125 may include a magnet generating a magnetic field. In one embodiment of the present invention, the first driving unit 125 of the stator 120 includes a coil.

The mover 130 is disposed inside the stator 120 , and the mover 130 includes a lens 135 . A second driving unit 138 for generating a magnetic field is mounted on the outer surface of the mover 130 .

In one embodiment of the present invention, when the first driving unit 125 of the stator 120 includes a coil, the second driving unit 138 of the mover 130 may include a magnet. Alternatively, when the first driving unit 125 of the stator 120 includes a magnet, the second driving unit 138 of the mover 130 may include a coil. In one embodiment of the present invention, the second driving unit 138 of the mover 130 includes, for example, a magnet.

One side of the elastic member 140 is fixed to the mover 130 , and the other side opposite to the one side is fixed to the stator 120 , and the elastic member 140 elastically supports the mover 130 .

In one embodiment of the present invention, the elastic member 140 includes a first elastic member 143 formed at the lower end of the outer circumferential surface of the mover 130 and a second elastic member 146 formed at the upper end of the outer circumferential surface of the mover 130 . may include

When a driving signal is not applied to the first driving unit 125 of the stator 120 or the second driving unit 138 of the mover 130 , the elastic member 140 moves the mover 130 to the upper surface of the base 110 . away from

The cover 150 is fixed to the base 110 , and the cover 150 surrounds the stator 120 and the mover 130 . Also, the cover 150 serves as an upper stopper that stops the mover 130 .

A shock absorbing member 155 is disposed on the cover 150 to prevent the mover 130 and the cover 150 from colliding and generating noise. The shock absorbing member 155 may include, for example, any one of a sponge, a synthetic resin having elasticity, and rubber.

Any one of the first driving unit 125 of the stator 120 or the second driving unit 138 of the movable member 130 in a state in which the mover 130 is spaced apart from the upper surface of the base 110 by the elastic member 140 . As a driving signal is applied to one, the mover 130 is moved in a direction toward the base 110 or in a direction toward the cover 150 . As a result, the distance between the lens 135 disposed inside the mover 130 and the image sensor disposed at the rear of the base 110 is adjusted, and the external light passing through the lens is focused on the image sensor.

Referring back to FIGS. 1 and 2 , in one embodiment of the present invention, when a driving signal is not applied to the first driving unit 125 of the stator 120 or the second driving unit 138 of the mover 130 . , the first stroke length SD1 formed by the lower surfaces of the base 110 and the mover 130 is shorter than the second stroke length SD2 formed by the upper surfaces of the cover 150 and the mover 130 .

The reason for forming the first stroke length SD1 shorter than the second stroke length SD2 as described above is that users mainly take pictures using the infinity focus of the camera module and take pictures using a specific focus only in special cases. Because.

Referring to the graph of FIG. 2 , to implement an infinity focus (distance from 1 m to 50 m to the subject) that is frequently used between the image sensor disposed at the rear of the base 110 and the lens 135 of the mover 130 . For this purpose, the mover 130 floating in a stationary state from the base 110 is driven to the base by a driving signal applied to the first driving unit 125 of the stator 120 or the second driving unit 138 of the mover 130 . The mover 130 is moved in the lower direction toward the upper surface of the 110 is in contact with the upper surface of the base 110, which is a lower stopper.

At this time, a first stroke length SD1 is provided between the lower surface of the floating mover 130 in a stationary state and the upper surface of the base 110 , and the stator 130 is in contact with the upper surface of the base 110 . The amount of current applied to 120 is C [mA].

Meanwhile, in order to implement infinity focus, a current of D [mA] (where D>C) is again applied to the stator 120 , and thus the mover 130 is spaced apart from the upper surface of the base 110 to the infinity focus position. is placed on The mover 130 corresponding to the infinity focus position is spaced apart from the upper surface of the base 110 by about 40 μm, as in the comparative example described above.

On the other hand, when photographing such as a close-up, a current of E [mA] is applied to the first driving unit 125 of the stator 120 or the second driving unit 138 of the movable element 130 , and the movable element 130 . ) is in contact with the cover 150, which is an upper stopper. In this case, the second stroke length SD2 is longer than the first stroke length SD1 between the upper surface of the floating mover 130 in the stationary state and the cover 150 .

Referring to FIG. 2 , in one embodiment of the present invention, the mover 130 first descends toward the base 110 by about 100 μm, and about 9 [mA] to drive the mover 130 by about 100 μm. A current of to about 10 [mA] is required.

As a result, in order to implement the mover 130 with low current and low power consumption when implementing infinity focus that is frequently used by the user, the first stroke length SD1 between the mover 130 and the base 110 is a cover It is preferable to form shorter than the second stroke length SD2 between 150 and the mover 130 .

In one embodiment of the present invention, the length of the second stroke length SD2 based on the first stroke length SD1 may be two to three times the first stroke length SD1.

Conversely, when the user frequently implements close-up focus, the first stroke length SD1 between the mover 130 and the base 110 is the cover 150 in order to implement the mover 130 with low current and low power consumption. and the second stroke length SD2 between the movers 130 may be formed longer than the second stroke length SD2 .

That is, in one embodiment of the present invention, the first stroke length SD1 between the mover 130 and the base 110 and the second between the cover 150 and the mover 130 according to the user's selection or tendency. The stroke length SD2 may be formed differently.

In one embodiment of the present invention, the first stroke length SD1 and the second stroke length SD2 may be changed according to the posture of the voice coil motor 100 .

For example, when the base 110 is disposed to face the ground as shown in FIG. 1 , the elastic member 140 droops toward the upper surface of the base 110 by the weight of the mover 130 , and Due to this, the first stroke length SD1 between the mover 130 and the base 110 is reduced and the second stroke length SD2 between the mover 130 and the cover 150 is increased, but even in this case The first stroke length SD1 is shorter than the second stroke length SD2 .

3 is a cross-sectional view illustrating an inverted state of the voice coil motor of FIG. 1 .

As shown in FIG. 3 , when the cover 150 is disposed to face the ground, the elastic member 140 droops toward the cover 150 due to the weight of the mover 130 . ) and the first stroke length SD1 between the base 110 is increased and the second stroke length SD2 between the mover 130 and the cover 150 is decreased, but even in this case, the first stroke length SD1 ) is formed to be shorter than the second stroke length SD2.

That is, in an embodiment of the present invention, the first stroke length SD1 is a length including the deflection length of the mover 130 .

4 is a conceptual diagram illustrating a voice coil motor according to another embodiment of the present invention.

Referring to FIG. 4 , the voice coil motor 100 includes a base 110 , a stator 120 , a mover 130 , an elastic member 140 , and a cover 150 .

The stator 120 is disposed on the base 110 , and the mover 130 coupled to the lens 135 is disposed on the base 110 corresponding to the inside of the stator 120 .

The elastic member 140 includes the stator 120 and the mover 130 so that the mover 130 floats from the upper surface of the base 110 when a driving signal such as a current is not applied to the stator 120 and the mover 130. It is coupled to 130 , and the cover 150 is coupled to the base 110 .

Hereinafter, the center positions of the upper and lower surfaces of the mover 130 will be defined as the first central portion 130a, and the position obtained by bisecting the lower surface of the cover 150 and the upper surface of the base 110 is the second central portion 130b. ) is defined as

In one embodiment of the present invention, when the infinity focus is frequently used, the first central portion 130a, which is a position in which the upper and lower surfaces of the mover 130 are bisected, is a cover ( The lower surface of the 150) and the upper surface of the base 110 are bisected and disposed below the second central portion 130b.

By disposing the first central portion 130a, which is a position in which the upper surface and the lower surface of the movable element 130 are bisected, lower than the second central portion 130b, in which the lower surface of the cover 150 and the upper surface of the base 110 are bisected. The first gap G1 formed between the base 110 and the mover 130 is narrower than the second gap G2 formed between the mover 130 and the cover 150 .

In addition, in one embodiment of the present invention, the first gap G1 formed between the base 110 and the mover 130 is the second gap G2 formed between the mover 130 and the cover 150 . It can be formed to be two to three times narrower.

As described in detail above, when a driving signal is not applied, the mover is made to float from the upper surface of the base, and the stroke length between the floating mover and the upper surface of the base or the stroke length between the movable mover and the cover in which a gap is floated Alternatively, it may be formed differently from the gap to realize low current or low power consumption characteristics.

Although the embodiments according to the present invention have been described above, these are merely exemplary, and those of ordinary skill in the art will understand that various modifications and equivalent ranges of embodiments are possible therefrom. Accordingly, the true technical protection scope of the present invention should be defined by the following claims.

100...voice coil motor 110...bass
120...Stator 130...Move
140...Elastic member 150...Cover

Claims (20)

a cover including an upper plate and a side plate extending from the upper plate;
a base coupled to the side plate of the cover;
a bobbin disposed between the upper plate of the cover and the base;
a coil disposed on the bobbin;
a magnet facing the coil; and
An elastic member coupled to the bobbin,
The bobbin is spaced apart from the upper plate of the base and the cover in an initial position where no current is applied to the coil,
The bobbin moves in a first direction approaching the base when a one-way current is supplied to the coil at the initial position and moves in a second direction approaching the upper plate of the cover when a second direction current is supplied,
the bobbin moves within a first stroke length in the first direction from the initial position and moves within a second stroke length in the second direction;
The length of the first stroke of the bobbin is shorter than the length of the second stroke of the bobbin,
The one-way current and the second-direction current supplied to the coil have opposite polarities. According to claim 1,
The distance between the lower surface of the bobbin and the upper surface of the base is shorter than the distance between the upper surface of the bobbin and the inner surface of the upper plate of the cover. According to claim 1,
The base limits the movement distance of the bobbin in the first direction,
The upper plate of the cover limits the movement distance of the bobbin in the second direction. According to claim 1,
The second stroke length is 2 to 3 times longer than the first stroke length. According to claim 1,
The first stroke length is a distance from the initial position of the bobbin to contact with the upper surface of the base,
The second stroke length is a distance from the initial position until the bobbin comes into contact with the inner surface of the upper plate of the cover. According to claim 1,
The lower surface of the bobbin and the upper surface of the base are regions in contact with each other,
The upper surface of the bobbin and the inner surface of the upper plate of the cover are regions in contact with each other. According to claim 1,
The bobbin overlaps the upper plate of the cover in the optical axis direction,
The bobbin is a lens driving device overlapping the base and the optical axis direction. According to claim 1,
The base includes a lower stopper adapted to contact the bobbin by movement of the bobbin,
and the cover includes an upper stopper adapted to contact the bobbin by movement of the bobbin. According to claim 1,
The cover is disposed to surround the bobbin, the coil, and the magnet. According to claim 1,
A lens driving device in which a shock absorbing member contacting the bobbin is disposed on an upper surface of the base. According to claim 1,
A lens driving device in which a shock absorbing member contacting the bobbin is disposed on an inner surface of the upper plate of the cover. According to claim 1,
A first imaginary line that bisects a second imaginary line connecting the lower surface of the bobbin from the upper surface of the bobbin is a third imaginary line that bisects a fourth imaginary line that connects the inner surface of the upper plate of the cover from the upper surface of the base; separated,
The second virtual line and the fourth virtual line are parallel to the first direction,
The first imaginary line is closer to the base than the third imaginary line. According to claim 1,
The bobbin is a lens driving device spaced apart from the base at a position for realizing infinity focus. image sensor;
The lens driving device of claim 1; and
and a lens coupled to the bobbin of the lens driving device. A mobile phone comprising the camera of claim 14 . a cover including an upper plate and a side plate extending from the upper plate;
a base coupled to the side plate of the cover;
a bobbin disposed between the upper plate of the cover and the base;
a coil disposed on the bobbin;
a magnet facing the coil; and
An elastic member coupled to the bobbin,
The bobbin is spaced apart from the upper plate of the base and the cover in an initial position where no current is applied to the coil,
The bobbin moves in a first direction approaching the base when a one-way current is supplied to the coil at the initial position and moves in a second direction approaching the upper plate of the cover when a second direction current is supplied,
A first distance between the base and the lower end of the bobbin in the initial position is closer than a second distance between the upper plate of the cover and the upper end of the bobbin,
The one-way current and the other-direction current supplied to the coil have opposite polarities. 17. The method of claim 16,
The base limits the movement distance of the bobbin in the first direction,
The upper plate of the cover limits the movement distance of the bobbin in the second direction. 18. The method of claim 17,
The bobbin moves in a first direction approaching the base when a one-way current is supplied to the coil and moves in a second direction approaching the upper plate of the cover when a second direction current is supplied,
the bobbin moves within a first stroke length in the first direction from the initial position and moves within a second stroke length in the second direction;
The first stroke length corresponds to the first distance between the base and the lower end of the bobbin and the second stroke length corresponds to the second distance between the upper plate of the cover and the upper end of the bobbin. drive. 17. The method of claim 16,
The bobbin is a lens driving device spaced apart from the base at a position for realizing infinity focus. 17. The method of claim 16,
The bobbin overlaps the upper plate of the cover in the optical axis direction,
The bobbin is a lens driving device overlapping the base and the optical axis direction.

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