KR20190057028A - Voice coil motor - Google Patents

Abstract

The present invention provides a voice coil motor capable of further reducing power consumption. The voice coil motor comprises: a stator including a first driving unit; a mover arranged in the stator, including a second driving unit responding to the first driving unit and having a lens mounted therein; a base fixing the stator; and an elastic member coupled to the mover and separating the mover from the base when a driving signal is not applied to the first or second driving unit. The mover is moved in a first direction approaching the base or a second direction away from the base. A first stroke length of the first direction of the mover and a second stroke length of the second direction of the mover are differently formed from each other.

Description

Voice coil motor {VOICE COIL MOTOR}

The present invention relates to a voice coil motor.

In recent years, mobile phones including a compact digital camera have been developed.

Conventionally, in the case of a miniature digital camera applied to a mobile phone or the like, the interval between the image sensor and the lens for changing the external light into a digital image or a digital image can not be adjusted. Recently, a voice coil motor The same lens driving device has been developed, so that it is possible to obtain an improved digital image or a digital image in a very small digital camera.

In general, a voice coil motor is equipped with a lens 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 surface of the base.

When the voice coil motor is not operated, the bobbin is always brought into 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.

 In order to drive the voice coil motor by driving the voice coil motor only in one direction, a driving force greater than the self-weight of the bobbin and the elastic force of the leaf spring is required, which increases the power consumption of the voice coil motor.

Further, in order to drive the voice coil motor, a driving force greater than the self-weight of the bobbin and the elastic force of the leaf spring is required, which increases the size of the coil wound around the magnet or the bobbin, thereby increasing the overall size of the voice coil motor.

The present invention provides a voice coil motor capable of driving the mover in both directions with a smaller current by floating the mover from the base, and further reducing power consumption when the infinite focusing area is used.

The technical object of the present invention is not limited to the above-mentioned technical objects and other technical objects which are not mentioned can be clearly understood by those skilled in the art from the following description will be.

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

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

According to the voice coil motor of the present invention, when the drive signal is not applied, the mover is caused to float from the upper surface of the base, and the stroke length or gap between the upper surface of the floating mover and the base It is possible to realize a low current or a low power consumption characteristic by being formed differently from the stroke length or the gap.

1 is a cross-sectional view of a voice coil motor according to an embodiment of the present invention.
2 is a graph showing current-distance characteristics of the voice coil motor of FIG.
Fig. 3 is a cross-sectional view showing the voice coil motor of Fig. 1 turned upside down. Fig.
4 is a cross-sectional view of a voice coil motor according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The sizes and shapes of the components shown in the drawings may be exaggerated for clarity and convenience. In addition, terms defined in consideration of the configuration and operation of the present invention may be changed according to the intention or custom of the user, the operator. The definitions of these terms should be interpreted based on the contents of the present specification and meanings and concepts in accordance with the technical idea of the present invention.

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

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 the shape of a plate having an opening at its center, and the base 110 serves as a lower stopper of the mover 130.

The upper surface of the base 110 may have a receiving groove for receiving the lower surface of the mover 130 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 from colliding with the base 110 to generate noise. The shock absorbing member 115 may include any one of, for example, a sponge, a synthetic resin having elasticity, and rubber.

The stator 120 is fixed on the base 110. The stator 120 includes a first driving part 125 for generating a magnetic field and a storage space is formed in the stator 120.

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

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

In an embodiment of the present invention, when the first driving part 125 of the stator 120 includes a coil, the second driving part 138 of the mover 130 may include a magnet. Alternatively, when the first driving part 125 of the stator 120 includes a magnet, the second driving part 138 of the mover 130 may include a coil. In one embodiment of the present invention, the second drive portion 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 of the elastic member 140 is fixed to the stator 120. The elastic member 140 elastically supports the mover 130. [

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 .

The elastic member 140 may move the mover 130 to the upper surface of the base 110 when the 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 cover 150 is fixed to the base 110 and the cover 150 covers the stator 120 and the mover 130. In addition, the cover 150 serves as a top stopper for stopping the mover 130.

The cover 150 is provided with an impact absorbing member 155 for preventing the mover 130 and the cover 150 from colliding with each other and generating noises. The shock absorbing member 155 may include, for example, a sponge, a synthetic resin having elasticity, and rubber.

The first driving part 125 of the stator 120 or the second driving part 138 of the mover 130 in a state where the mover 130 is separated from the upper surface of the base 110 by the elastic member 140 The mover 130 is moved in the direction toward the base 110 or in the direction toward the cover 150. [ As a result, the distance between the lens 135 disposed inside the mover 130 and the image sensor disposed behind the base 110 is adjusted, and the external light having passed through the lens is focused on the image sensor.

1 and 2, when the driving signal is not applied to the first driving part 125 of the stator 120 or the second driving part 138 of the mover 130 in the embodiment of the present invention, The first stroke length SD1 formed by the base 110 and the lower surface of the mover 130 is shorter than the second stroke length SD2 formed by the cover 150 and the upper surface of the mover 130. [

The reason why the first stroke length SD1 is shorter than the second stroke length SD2 is because the user takes a picture mainly by using the infinity focus of the camera module and shoots the picture by using a specific focus only in a special case Because.

2, infinity focus (distance 1 m to 50 m from the subject) frequently used between the image sensor disposed at the rear of the base 110 and the lens 135 of the mover 130 is implemented The mover 130 floating from the base 110 in a stationary state is driven by the driving signal applied to the first driving part 125 of the stator 120 or the second driving part 138 of the mover 130, The movable member 130 is moved downward toward the upper surface of the base 110. The movable member 130 is brought into contact with the upper surface of the base 110 as a lower stopper.

A first stroke length SD1 is provided between the lower surface of the mover 130 in a floating state and the upper surface of the base 110. In order for the mover 130 to contact the upper surface of the base 110, The amount of current applied to the capacitor 120 is C [mA].

Meanwhile, in order to realize the infinity focus, a current of D [mA] (D> C) is applied to the stator 120 and the mover 130 is separated from the upper surface of the base 110, . The mover 130 corresponding to the infinity focus position is spaced apart from the upper surface of the base 110 by about 40 占 퐉 as in the above-described comparative example.

On the other hand, when photographing a close-up photograph or the like, a current of E [mA] is applied to the first driving part 125 of the stator 120 or the second driving part 138 of the mover 130, Is brought into contact with the cover 150 which is the upper stopper. At this time, between the upper surface of the mover 130 in the floating state and the cover 150, the second stroke length SD2 is longer than the first stroke length SD1.

Referring to FIG. 2, in an embodiment of the present invention, the mover 130 first descends toward the base 110 by about 100 mu m, and about 9 mu m to drive the mover 130 to about 100 mu m. To about 10 [mA] is required.

As a result, the first stroke length SD1 between the mover 130 and the base 110 in order to realize the mover 130 with low current and low power consumption when implementing the infinite focus frequently used by the user, Is shorter than the second stroke length (SD2) between the movable member (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.

The first stroke length SD1 between the mover 130 and the base 110 is set to be smaller than the first stroke length SD1 in order to realize the mover 130 with a low current and a low power consumption when the user frequently implements the close focus. And the second stroke length (SD2) between the mover (130).

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 stroke length SD2 between the cover 150 and the mover 130 are determined by the user's selection or propensity. The stroke length SD2 can be formed differently from each other.

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 is sagged toward the upper surface of the base 110 by the self weight of the mover 130 This reduces the first stroke length SD1 between the mover 130 and the base 110 and increases the second stroke length SD2 between the mover 130 and the cover 150, The first stroke length SD1 is formed to be shorter than the second stroke length SD2.

Fig. 3 is a cross-sectional view showing the voice coil motor of Fig. 1 turned upside down. Fig.

3, when the cover 150 is disposed to face the ground, the elastic member 140 sags toward the cover 150 due to the self weight of the mover 130, which causes the mover 130 The first stroke length SD1 between the mover 130 and the cover 110 is increased and the second stroke length SD2 between the mover 130 and the cover 150 is reduced but also the first stroke length SD1 Is formed to have a length shorter than the second stroke length SD2.

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

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

4, the voice coil motor 100 includes a base 110, a stator 120, a mover 130, an elastic member 140, and a cover 150. As shown in Fig.

A stator 120 is disposed on the base 110 and a 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 is fixed to the stator 120 and the movable element 130 so that the movable element 130 floats from the upper surface of the base 110 when no driving signal such as current is applied to the stator 120 and the movable element 130. [ 130, and the cover 150 is coupled to the base 110.

The center position of the upper surface and the lower surface of the mover 130 is defined as the first center portion 130a and the position where the lower surface of the cover 150 and the upper surface of the base 110 are bisected is referred to as a second center portion 130b ).

In one embodiment of the present invention, in order to realize the low current characteristic and the low power consumption characteristic when the infinity focus is frequently used, the first center portion 130a, which is the position where the upper surface and the lower surface of the mover 130 are bisected, 150 and the upper surface of the base 110, as shown in FIG.

By disposing the first central portion 130a which is the position where the upper surface and the lower surface of the mover 130 are bisected below the second central portion 130b which bisects the lower surface of the cover 150 and the upper surface of the base 110 The first gap G1 formed between the base 110 and the mover 130 is formed to be narrower than the second gap G2 formed between the mover 130 and the cover 150. [

The first gap G1 formed between the base 110 and the mover 130 may be a gap G2 formed between the mover 130 and the cover 150. In this case, To about two-fold to three-fold.

As described above in detail, when the drive signal is not applied, the mover is caused to float from the upper surface of the base, and the stroke length or gap between the upper surface of the floating mover and the base is equal to the stroke length Or a gap can be formed to realize low current or low power consumption characteristics.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims. Accordingly, the true scope of the present invention should be determined by the following claims.

100 ... Voice coil motor 110 ... Base
120 ... stator 130 ... mover
140 ... elastic member 150 ... cover

Claims (20)

A cover including a top plate and a side plate extending from the top plate;
A base coupled to the side plate of the cover;
A bobbin disposed between the upper plate and the base of the cover;
A coil disposed in the bobbin;
A magnet facing the coil; And
And an elastic member coupled to the bobbin,
The bobbin being spaced from the base and the top plate of the cover at an initial position where no current is applied to the coil,
The bobbin moves in a first direction to approach the base when a unidirectional current is supplied to the coil at the initial position and in a second direction to approach the upper plate of the cover when a current in the other direction is supplied,
The bobbin moves within a first stroke length in the first direction at the initial position and within a second stroke length in the second direction,
Wherein the first stroke length of the bobbin is shorter than the second stroke length of the bobbin. The method according to claim 1,
Wherein the second stroke length is two to three times longer than the first stroke length. The method according to claim 1,
The base limits the movement distance of the bobbin in the first direction,
And the upper plate of the cover limits a moving distance of the bobbin in the second direction. The method according to claim 1,
Wherein the first stroke length is a distance from the initial position of the bobbin to an upper surface of the base. 5. The method of claim 4,
And the second stroke length is a distance from when the bobbin contacts the inner surface of the top plate of the cover at the initial position. 6. The method of claim 5,
Wherein 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. The method according to claim 6,
Wherein the one-way current supplied to the coil and the other direction current are opposite in polarity to each other. The method according to claim 1,
And the cover is disposed so as to surround the bobbin, the coil, and the magnet. The method according to claim 1,
Wherein the bobbin is movable to a position where the bobbin comes into contact with the upper plate of the cover at a position where the bobbin comes into contact with the upper surface of the base. The method according to claim 1,
And an impact absorbing member contacting the bobbin is disposed on an upper surface of the base. The method according to claim 1,
And an impact absorbing member that is in contact with the bobbin is disposed on an inner surface of the upper plate of the cover. The method according to claim 1,
A first imaginary line bisecting a second imaginary line connecting the lower surface of the bobbin on an upper surface of the bobbin is divided into a third imaginary line bisecting a fourth imaginary line connecting the upper surface of the base to the inner surface of the upper plate, Apart,
The second virtual line and the fourth virtual line are parallel to the first direction,
Wherein the first virtual line is closer to the base than the third virtual line. The method according to claim 1,
Wherein the bobbin is spaced from the base at a position for realizing infinite focus. Image sensor;
A lens driving device according to claim 1; And
And a lens coupled to the bobbin of the lens driving device. 15. A mobile phone comprising the camera of claim 14. A cover including a top plate and a side plate extending from the top plate;
A base coupled to the side plate of the cover;
A bobbin disposed between the upper plate and the base of the cover;
A coil disposed in the bobbin;
A magnet facing the coil; And
And an elastic member coupled to the bobbin,
The bobbin being spaced from the base and the top plate of the cover at an initial position where no current is applied to the coil,
Wherein the first distance between the base and the lower end of the bobbin at the initial position is closer to the second distance between the top plate of the cover and the upper end of the bobbin. 17. The method of claim 16,
The bobbin moves in a first direction to approach the base when a unidirectional current is supplied to the coil and in a second direction to approach the upper plate of the cover when a current in the other direction is supplied,
The bobbin moves within a first stroke length in the first direction at the initial position and within a second stroke length in the second direction,
Wherein 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 top plate of the cover and the upper end of the bobbin, drive. 17. The method of claim 16,
Wherein the second distance is two to three times longer than the first distance. 17. The method of claim 16,
Wherein the bobbin is spaced from the base at a position for realizing infinite focus. A cover including a top plate and a side plate extending from the top plate;
A base coupled to the side plate of the cover;
A bobbin disposed between the upper plate and the base of the cover;
A coil disposed in the bobbin;
A magnet facing the coil; And
And an elastic member coupled to the bobbin,
Wherein the bobbin is spaced from the base and the top plate of the cover at an initial position where no current is applied to the coil.

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