KR102239275B1 - Voice coil motor and method for driving thereof - Google Patents

Abstract

The voice coil motor includes a base; A cover including an upper plate and a side plate extending from the upper plate and coupled to the base; A stator disposed in the cover; A bobbin disposed in the stator; A first driving part disposed on the stator; A second driving unit disposed on the bobbin and facing the first driving unit; An elastic member coupled to the bobbin; And a position sensor disposed on the stator, wherein the bobbin moves in a first direction away from the base or in a second direction closer to the base, and the position sensor The distance to the upper surface is fixed, and the position sensor is disposed between the second driving part and the side plate of the cover.

Description

Voice coil motor and its driving method {VOICE COIL MOTOR AND METHOD FOR DRIVING THEREOF}

The present invention relates to a voice coil motor and a driving method thereof.

Recently, a mobile phone with a built-in micro digital camera has been developed.

In the case of conventional ultra-small digital cameras applied to mobile phones, etc., it was not possible to adjust the distance between the image sensor and the lens that converts external light into a digital image or digital image, but recently, a voice coil motor and a voice coil motor that adjusts the distance between the image sensor and the lens. The same lens driving device has been developed to obtain an improved digital image or digital image from a micro digital camera.

In general, a voice coil motor has a lens mounted therein, and a bobbin disposed on an upper surface of the base moves upward from the base to adjust the distance between the lens and an image sensor disposed at the rear 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 is not operated, the bobbin is always in contact with the base by the elastic force of the leaf spring. That is, the bobbin of the conventional voice coil motor is driven in one direction toward the top with respect to the base.

Since the conventional voice coil motor is driven only in one direction, 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, and thus the power consumption of the voice coil motor is greatly increased.

In addition, 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, so the size of the coil wound around the magnet or the bobbin increases, thereby increasing the overall size of the voice coil motor.

In addition, when the shape of the leaf spring is deformed, there is a problem in that the focus between the lens and the image sensor is not accurately achieved, so that the image quality is significantly lowered.

On the other hand, if power consumption is reduced by separating the bobbin with a lens from the base among the voice coil motors, the position of the bobbin separated from the base is changed, making it difficult to precisely control the focus, it is difficult to continuously focus, and the position of the bobbin changes. Accordingly, unnecessary power consumption is consumed.

US Patent Application Publication No. US 2007/0047942 (published on Mar. 01, 2007)

The present invention enables low-power driving by separating a mover equipped with a lens from the upper surface of the base when a drive signal is not applied, and adjusting the distance between the lens and the image sensor by the drive signal, and sensing the position of the mover to precisely adjust the focus. It provides a voice coil motor that can be adjusted continuously, focus can be adjusted continuously, and prevent unnecessary power consumption.

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

In one embodiment, the voice coil motor includes a base; A cover including an upper plate and a side plate extending from the upper plate and coupled to the base; A stator disposed in the cover; A bobbin disposed in the stator; A first driving part disposed on the stator; A second driving unit disposed on the bobbin and facing the first driving unit; An elastic member coupled to the bobbin; And a position sensor disposed on the stator, wherein the bobbin moves in a first direction away from the base or in a second direction closer to the base, and the position sensor The distance to the upper surface is fixed, and the position sensor is disposed between the second driving part and the side plate of the cover.

According to the voice coil motor and its driving method according to the present invention, a position sensor that senses the displacement of the mover with respect to the stator is mounted on at least one of the stator or the mover operated with respect to the stator to accurately determine the current position of the mover. By driving the ruler, the focusing function can be implemented in a faster time, and the power consumption can be greatly reduced by removing unnecessary driving sections of the mover.

1 is a conceptual diagram of a voice coil motor according to an embodiment of the present invention.
2 is a conceptual diagram of a voice coil motor according to another embodiment of the present invention.
3 is a conceptual diagram of a voice coil motor according to another embodiment of the present invention.
4 is a flowchart illustrating a method of driving a voice coil motor according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this process, the size or shape of the components illustrated in the drawings may be exaggerated for clarity and convenience of description. In addition, terms specifically defined in consideration of the configuration and operation of the present invention may vary according to the intention or custom of users or operators. 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 the present specification.

1 is a conceptual diagram of a voice coil motor according to an embodiment of the present invention.

Referring to FIG. 1, the voice coil motor 100 includes a base 110, a stator 120, a mover 130, an elastic member 140, and a position sensor 150.

The base 110 serves to support the stator 120 and the mover 130.

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The base 110 is formed with an opening penetrating the upper and lower surfaces of the base 110, and the opening is formed at a position corresponding to the lens 132 of the mover 130 to be described later. An image sensor 115 for generating a digital image or moving picture corresponding to light incident through the opening may be disposed on the rear or rear of the base 110.

The stator 120 is disposed on the base 110 and the stator 120 is not driven.

The fixed stator 120 includes a first driving unit 125 for driving the mover 130 to be described later, and the first driving unit 125 generates a first magnetic field. In one embodiment of the present invention, the first driving unit 125 may include a plurality of magnets.

The mover 130 is disposed inside the stator 120, and the mover 130 includes a lens 132, a bobbin 134, and a second driving unit 136.

The bobbin 134 of the mover 130 is formed in, for example, a cylindrical shape with open upper and lower surfaces, and the lens 132 is coupled to the inner surface of the bobbin 134. For example, the lens 132 may be coupled to the inner surface of the bobbin 134 by a screw method.

The second driving part 136 is disposed on the outer surface of the bobbin 134. In one embodiment of the present invention, the second driving unit 136 may include a coil block. The coil block is formed by winding a long wire insulated or coated by an insulating resin.

The coil block may be wound in a cylindrical shape and disposed on the outer surface of the bobbin 134 or may be directly wound on the outer surface of the bobbin 134.

The second driving unit 136 including the coil block reacts with the first magnetic field by a driving signal such as current to generate a second magnetic field that generates attractive force or repulsive force.

The elastic member 140 serves to elastically support the mover 130 by being coupled to the stator 120 and the mover 130.

In one embodiment of the present invention, the elastic member 140 may include, for example, a leaf spring, and the elastic member 140 is coupled to the lower and upper portions of the bobbin 134 of the mover 130, respectively. Can be.

In one embodiment of the present invention, the mover 130 elastically coupled to the elastic member 140 is the upper surface of the base 110 when a driving signal is not applied to the second driving unit 136 including the coil block. It is spaced a predetermined distance from.

When the mover 130 is spaced apart from the upper surface of the base 110, the mover 130 is moved away from the upper surface of the base 110 according to the direction of the current, which is a driving signal applied to the second driving unit 136, or It is possible to drive in both directions in a direction closer to the upper surface of the base 110, and thus, the voice coil motor 100 can drive a low current and greatly reduce power consumption.

On the other hand, when the mover 130 is spaced apart from the upper surface of the base 110, that is, when the mover 130 is floating from the upper surface of the base 110, the reference position of the mover 130 or of the mover 130 It is difficult for the controller to determine the current location, and thus, unnecessary power consumption may be generated as the mover 130 is unnecessarily driven.

In one embodiment of the present invention, the position sensor 150 is disposed on the second driving unit 136 including the coil block facing the first driving unit 125 including a magnet.

The position sensor 150 outputs a sensing signal for the reference position and/or the current position of the mover 130 to a control unit (not shown), and the control unit is a coil block in response to the sensing signal output from the position sensor 150. A driving signal suitable for the second driving unit 136 is provided.

In one embodiment of the present invention, the position sensor 150 is connected to a hall sensor, a hall sensor, which is one of magnet sensors suitable for sensing the position of the mover 130 according to a change in a magnetic field to drive power. And a wire for applying and outputting a sensing signal, and the wire may be electrically connected to a circuit board disposed on a rear surface of the base 110 to generate a driving signal.

One position sensor 150 may be disposed on the second driving unit 136 in consideration of production cost, but differently, a plurality of position sensors 150 may be disposed on the second driving unit 136 at equal intervals.

2 is a conceptual diagram of a voice coil motor according to another embodiment of the present invention. The voice coil motor according to another embodiment of the present invention has substantially the same configuration as the voice coil motor described in FIG. 1 except for the arrangement of the first and second driving units and the position sensor. Accordingly, redundant descriptions of the same components will be omitted, and the same names and the same reference numerals will be assigned to the same components.

Referring to FIG. 2, the voice coil motor 100 includes a base 110, a stator 120, a mover 130, an elastic member 140, and a position sensor 160.

The stator 120 includes a first driving unit 127 that generates a first magnetic field, and in one embodiment of the present invention, the first driving unit 127 is a long wire insulated by an insulating resin and wound in a cylindrical shape. It may include a coil block.

In addition, on the outer circumferential surface of the bobbin 134 of the mover 130 disposed inside the stator 120, a second driving unit 138 for generating a second magnetic field that generates attractive force or repulsive force in response to the first magnetic field is disposed. do.

In one embodiment of the present invention, the second driving unit 138 facing the first driving unit 127 including a coil block may include a plurality of magnets.

The position sensor 160 may be, for example, a Hall sensor, and the position sensor 160 may be disposed on the inner surface of the first driving unit 127 that faces the second driving unit 138 and includes a coil block. have.

The position sensor 160 senses a change in the second magnetic field generated from the second driving unit 138 according to the movement of the mover 130 and outputs a sensing signal corresponding to the current position of the mover 130.

The position sensor 160 outputs a sensing signal for the reference position and/or the current position of the mover 130 to a control unit (not shown), and the control unit is a coil block in response to the sensing signal output from the position sensor 160. A driving signal suitable for the first driving unit 127 is provided.

3 is a conceptual diagram of a voice coil motor according to another embodiment of the present invention. The voice coil motor according to another embodiment of the present invention has substantially the same configuration as the voice coil motor described in FIG. 1 except for the arrangement of the elastic member and the mover. Accordingly, redundant descriptions of the same components will be omitted, and the same names and the same reference numerals will be assigned to the same components.

Referring to FIG. 3, the voice coil motor 100 includes a base 110, a stator 120, a mover 130, an elastic member 145, and a position sensor 150.

The stator 120 includes a first driving unit 125, and the first driving unit 125 includes at least one magnet generating a first magnetic field.

The mover 130 is disposed inside the stator 120, and the mover 130 includes a second driving unit 136 facing the first driving unit 125. The second driving unit 136 includes a coil block wound around an insulated long wire, and the second driving unit 136 generates a second magnetic field that generates attractive force or repulsive force by acting with the first magnetic field.

The elastic member 145 is coupled to the mover 130 and the stator 120, and the mover 130 is elastically coupled by the elastic member 145.

In one embodiment of the present invention, the mover 130 coupled to the elastic member 145 is in contact with the upper surface of the base 110 when a driving signal is not applied to the second driving unit 136, and the mover 130 ) Is spaced apart from the upper surface of the base 110 when a driving signal is applied to the second driving unit 136.

The position sensor 150 is, for example, disposed on the second driving unit 136, and the position sensor 150 senses a change in the magnetic field generated as the mover 130 is separated from the upper surface of the base 110 To output a sensing signal.

The position sensor 150 outputs a sensing signal for the reference position and/or the current position of the mover 130 to a control unit (not shown), and the control unit is a coil block in response to the sensing signal output from the position sensor 150. A driving signal suitable for the second driving unit 136 is provided.

4 is a flowchart illustrating a method of driving a voice coil motor according to an embodiment of the present invention.

1 and 4, in order to drive the voice coil motor 100, a step of first sensing the reference position or the current position of the mover 130 having the lens 132 through the position sensor 150 is performed. (Step S10)

Specifically, the position sensor 150 is disposed on the base 110 and up-down with respect to the stator 120 and the stator 120 having a first driving unit 125 and a mover having a second driving unit 136 It is placed in any one of (130).

For example, when the first driving unit 125 includes a magnet and the second driving unit 136 includes a coil block, the position sensor 150 such as a hall sensor is the first driving unit 125 It is disposed on the second driving unit 136 facing the.

Conversely, when the first driving unit 125 includes a coil block and the second driving unit 136 includes a magnet, the position sensor 150 is positioned at the first driving unit 125 facing the second driving unit 136. Is placed.

In this case, when a driving signal is not applied to the first and second driving units 125 and 136, the mover 130 may be in a floating state separated from the upper surface of the base 110.

Alternatively, when a driving signal is not applied to the first and second driving units 125 and 136, the mover 130 may be in a state disposed on the upper surface of the base 110.

Subsequently, the sensing signal generated from the position sensor 150 is applied to the controller, and the controller determines the current position of the mover 130 in response to the sensing signal generated from the position sensor 150 (step S20).

Subsequently, the control unit determines the level of the driving signal for adjusting the distance between the image sensor and the lens included in the mover 130 based on the sensing signal generated from the position sensor 150 (step S30).

Subsequently, the control unit applies a driving signal to one of the first and second driving units 125 and 136 to adjust the distance between the lens and the image sensor (step S40).

As described in detail above, a position sensor that senses the displacement of the mover with respect to the stator is mounted on at least one of the stator or the mover operated with respect to the stator to accurately determine the current position of the mover, thereby driving the mover to perform a focusing function. It can be implemented in a faster time, and has the effect of greatly reducing power consumption by removing unnecessary driving sections of the mover.

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. Therefore, the true technical protection 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 150,160...position sensor

Claims (12)

Base;
A cover including an upper plate and a side plate extending from the upper plate and coupled to the base;
A stator disposed in the cover;
A bobbin disposed in the stator;
A first driving part disposed on the stator;
A second driving unit disposed on the bobbin and facing the first driving unit;
And a position sensor disposed on the stator,
The bobbin is moved in a first direction away from the base or in a second direction closer to the base,
The position sensor has a fixed distance to the upper surface of the base even if the bobbin is moved,
The position sensor is disposed between the second driving part and the side plate of the cover,
The position sensor is a voice coil motor disposed to protrude inward from an inner surface of the first driving part.
The method of claim 1,
The first driving unit includes a coil,
The second driving unit voice coil motor including a magnet.
The method of claim 2,
Voice coil motor comprising an elastic member coupled to the bobbin.
The method of claim 1,
The position sensor is a voice coil motor comprising a Hall sensor that detects a change in a magnetic field, and a wire connected to the Hall sensor and electrically connected to a circuit board disposed on a lower surface of the base so that external power is supplied.
The method of claim 2,
A voice coil motor in which a current direction applied to the coil when the bobbin moves in a first direction and a current direction applied to the coil when the bobbin moves in a second direction are opposite to each other.
The method of claim 3,
The elastic member is disposed between an upper portion of the bobbin and the stator to support the bobbin, and the first elastic member is disposed symmetrically to the first elastic member between the lower portion of the bobbin and the stator to support the bobbin. Voice coil motor comprising a second elastic member.
The method of claim 2,
Voice coil motor further comprising a control unit for providing a driving signal to the coil in response to the sensing signal of the position sensor.
The method of claim 2,
The position sensor is a voice coil motor in which a plurality of positions are arranged at equal intervals on the surface of the coil.
The method of claim 3,
At an initial position where no current is applied to the coil, the bobbin is elastically supported by the elastic member and is disposed between the base and the cover.
The method of claim 2,
The coil is wound in a cylindrical shape on the inner surface of the stator to form a coil block, the coil block has an upper surface, an inner surface and a lower surface, and the lower surface of the coil is disposed to face the base, and the A voice coil motor having an upper surface of the coil block facing the cover.
The method of claim 3,
The elastic member is a voice coil motor that forms a first gap between the base and the bobbin and a second gap between the bobbin and the cover at an initial position where no current is applied to the coil.



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