KR102669937B1 - Camera module - Google Patents

Abstract

The present invention relates to a camera module.
That is, the present invention includes a mover including a lens and formed with a first driving part; a stator formed with the first driving part and a second driving part that drives the mover by the action of electromagnetic force; The stator includes a base on which the stator is fixed, and when the lens is in an up position or a side position, the movable member is in contact with the base, and when the lens is in a down position, the movable member is in contact with the base. It is spaced apart from the base.

Description

Camera module {CAMERA MODULE}

The present invention relates to a camera module.

Recently, mobile phones and tablet PCs with built-in ultra-small camera modules have been developed.

In the case of conventional digital camera modules applied to mobile phones, etc., it was not possible to adjust the gap between the image sensor and lens, which changes external light into a digital image or digital image, but recently, voice coil motors that adjust the gap between the image sensor and lens are used. The same lens driving device was developed, making it possible to obtain improved digital images or digital videos from the camera module.

In a voice coil motor generally applied to a camera module, a mover with a lens mounted inside moves from the base to the top to adjust the gap between the lens and the image sensor placed on the back of the base.

A conventional voice coil motor has a structure in which an elastic member presses the mover into contact with the base when a drive signal is not applied.

That is, in a conventional voice coil motor, because the elastic member presses the mover, the electromagnetic force for driving the mover must be greater than the elastic force of the elastic member and the self-weight of the mover in order for the mover to be separated from the base.

Additionally, the mover of a conventional voice coil motor has a displacement of about 30㎛ to 50㎛ depending on the posture of the voice coil motor.

However, the mover of the conventional voice coil motor not only has displacement depending on the posture of the voice coil motor, but also includes an undriven section that is not driven even when a drive signal is applied, but the mover is driven by an auto-focusing algorithm that does not reflect this, resulting in auto-focusing. It has the problem that it takes a lot of time.

The present invention solves the problem of reducing the current consumption of a camera module.

The present invention,

a mover including a lens and having a first driving portion;

a stator formed with the first driving part and a second driving part that drives the mover by the action of electromagnetic force;

It includes a base on which the stator is fixed,

When the lens is in an up position or a side position, the movable member is in contact with the base, and when the lens is in a down position, the movable member is provided with a camera module spaced apart from the base. do.

And, in one embodiment of the present invention, the first driving part may be a wound coil and the second driving part may be a magnet, or the first driving part may be a magnet and the second driving part may be a wound coil.

Additionally, when the lens is in the up position, when a current less than the reference current is applied to the coil, the mover is not driven, and when a current greater than the reference current is applied to the coil, the mover may be driven.

Additionally, the start current that drives the mover in the side position may be smaller than the start current that drives the mover in the up position.

Additionally, the starting current in the side posture may be 0-10 mA.

The present invention,

a mover including a lens and having a first driving portion;

a stator formed with the first driving part and a second driving part that drives the mover by the action of electromagnetic force;

It includes a base on which the stator is fixed,

When the lens is in an up position, the mover is in contact with the base, and when the lens is in a side position or down position, the mover is provided with a camera module spaced apart from the base. do.

In one embodiment of the present invention, the base is formed in the shape of a plate with an opening through which light passes in the center, the base serves as a lower stopper of the mover, and an image sensor is disposed on the rear of the base. And the stator can be fixed on the base.

In addition, it may further include an elastic member that has one side fixed to the mover and the other side opposite to the one side fixed to the stator to elastically support the mover.

Additionally, when the lens is in a down position, the mover can be driven in the reverse direction.

The present invention,

a mover including a lens;

Includes an actuator that drives the mover,

When the lens is in an up position or side position, the movable member is in contact with a base that functions as a stopper for the movable member, and when the lens is in a down position, the movable member is spaced apart from the base. Or,

Alternatively, when the lens is in an up position, the movable member is in contact with the base, and when the lens is in a side position or down position, a camera module is provided in which the movable member is spaced apart from the base. do.

In one embodiment of the present invention, the actuator may be one of a voice coil motor (VCM) actuator, an actuator driven by piezoelectric force, or a MEMS actuator driven by a capacitance method. .

In addition, a posture detection sensor that determines one of the up, side, and down postures of the lens and outputs posture data; an image signal processor (ISP) that generates a driving signal for driving the actuator using the posture data output from the posture detection sensor; It may further include an image sensor that changes the light passing through the lens into a digital signal.

Additionally, the posture sensor may include a gyro sensor that detects the direction of gravity.

And, when the lens is in a down position, the mover can be driven in the reverse direction.

In addition, when the lens is in the up position and a current greater than the reference current is applied to the coil, the mover may be driven.

The present invention has the effect of detecting the posture of a voice coil motor or lens, controlling the voice coil motor with this posture data, reducing current consumption, and driving the camera module optimally.

In addition, the present invention reduces current consumption by eliminating mechanical offset in the actuator, increases the design freedom of electromagnetic force, and solves the defocus problem by applying current in the opposite direction even when a change in the spring occurs. This has the effect of improving the yield of the camera module by eliminating the need for initial focusing.

1 is a block diagram showing a camera module according to an embodiment of the present invention.
Figure 2 is a conceptual cross-sectional view to explain that the lens of the camera module according to an embodiment of the present invention is located in the upper direction.
Figure 3 is a conceptual cross-sectional view to explain that the lens of the camera module according to an embodiment of the present invention is located in the side direction.
Figure 4 is a conceptual cross-sectional view to explain that the lens of the camera module according to an embodiment of the present invention is located in the downward direction.
Figure 5 is a graph showing current-distance characteristics according to the posture of the camera module according to an embodiment of the present invention.

Hereinafter, an embodiment according to the present invention will be described in detail with reference to the attached drawings. In this process, the size or shape of the components shown in the drawings may be exaggerated for clarity and convenience of explanation. Additionally, 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 made based on the content throughout this specification.

Figure 1 is a block diagram showing a camera module according to an embodiment of the present invention.

Referring to FIG. 1, the camera module 800 includes a voice coil motor 100 driven in one direction, a posture detection sensor 200, an autofocus algorithm 300, an image signal processor 400, an image sensor 500, and Includes a control unit 600.

Here, the voice coil motor 100 includes a mover including a lens and is driven by electromagnetic force to perform auto-focusing of the camera module 800.

In addition, the posture detection sensor 200 determines the posture of the voice coil motor 100 or the lens and outputs posture data, and the image signal processor (ISP) 400 is the posture detection sensor ( Driving to drive the voice coil motor using the optimal focus value of the lens calculated by the autofocus algorithm 300 with posture data corresponding to the posture of the voice coil motor 100 output from 200) generates a signal.

Here, the posture sensor 200 may include a gyro sensor that detects the direction of gravity.

In addition, the autofocus algorithm 300 detects the optimal focus value of the voice coil motor 100 according to the distance to the subject and outputs a detection signal in order to accurately implement autofocusing and implement a fast autofocusing response time.

At this time, the autofocus algorithm 300 may be used in the form of an algorithm inside the image signal processor 400, or may be used by being built into a chip separate from the image sensor processor 400.

Therefore, the posture detection sensor 200 senses three postures of the voice coil motor 100 or the lens, as described later.

Here, the posture detection sensor 200 can sense three or more postures of the voice coil motor 100 or the lens. However, in one embodiment of the present invention, for convenience of explanation, the posture detection sensor 200 uses a voice coil motor ( 100) Alternatively, we will explain sensing three postures, including the up posture, side posture, and down posture of the lens.

In addition, the image sensor 500 changes the light passing through the lens into a digital signal, and the control unit 600 controls the voice coil motor 100, the posture detection sensor 200, and the image signal processor 400. ) and controls the image sensor 500.

In addition, the control unit 500 is connected to the voice coil motor 100, the posture detection sensor 200, the image signal processor 400, and the image sensor 500 through a data bus and/or control bus.

Therefore, the present invention has the advantage of detecting the posture of the voice coil motor or lens, controlling the voice coil motor with this posture data, reducing current consumption, and driving the camera module optimally.

Figure 2 is a conceptual cross-sectional view to explain that the lens of the camera module according to an embodiment of the present invention is located in the upper direction, and Figure 3 is a conceptual cross-sectional view showing that the lens of the camera module according to an embodiment of the present invention is located in the side direction. This is a conceptual cross-sectional view for explanation, and Figure 4 is a conceptual cross-sectional view to explain that the lens of the camera module according to an embodiment of the present invention is located in the downward direction.

As described above, Figure 2 shows an up posture with the lens of the camera module positioned in the upward direction, and the "up posture" refers to the position of the lens 135 of the mover 130 of the voice coil motor. It can be defined as a posture in which the optical axis is formed in a direction perpendicular to the ground and the base 110 is disposed to face the ground.

In addition, Figure 3 shows a side posture in which the lens of the camera module is located in the side direction. The "side posture" refers to the position where the optical axis of the lens 135 of the mover 130 of the voice coil motor is positioned on the ground. It can be defined as a posture in which the base 110 is formed in a direction parallel to the ground and arranged perpendicularly to the ground.

In addition, Figure 4 shows a down posture in which the lens of the camera module is located in the downward direction, and "down posture" refers to the position of the lens 135 of the mover 130 of the voice coil motor 100. It can be defined as a posture in which the optical axis is formed in a direction perpendicular to the ground and the cover 150 is disposed to face the ground.

Here, the camera module according to an embodiment of the present invention includes a movable element 130 including a lens 135 and a first driving part 138, and the movement is performed by the action of the first driving part 138 and electromagnetic force. It includes a stator 120 on which a second driving unit 125 that drives the ruler 130 is formed, and a base 110 on which the stator 120 is fixed, and the lens 135 is in an up position. Alternatively, in the case of the side posture, the movable member 130 is in contact with the base 110, and when the lens 135 is in the down posture, the movable member 130 is in contact with the base 110. ) and is spaced apart.

In addition , when the lens 135 is in an up position or side position, the camera module has some offset, and when the lens 135 is in a down position, the movable member 130 ), the offset may disappear due to deflection due to its own weight in the direction of gravity.

At this time, the mover 130, stator 120, and base 110 may be parts of the voice motor coil 100.

Referring to FIG. 2, the voice coil motor 100 drives the lens 135 to perform an auto-focusing function.

For example, the lens 135 mounted on the voice coil motor 100 moves in an upward direction from the base 110, and in this process, a focusing operation occurs between the lens 135 and the image sensor 500. It is carried out.

The voice coil motor 100 may include a base 110, a stator 120, a mover 130, an elastic member 140, and a cover 150.

Additionally, the base 110 is formed in the shape of a plate with an opening through which light passes in the center, and the base 110 serves as a lower stopper of the mover 130.

Additionally, the image sensor 500 may be disposed on the rear of the base 110 or at the rear of the base 110. The image sensor 500 changes the light focused through the lens of the mover 130 into a digital image or video.

Additionally, the stator 120 is fixed on the base 110.

Here, the first driving unit 138 may be a magnet, and the second driving unit 125 may be a wound coil.

Conversely, the first driving unit 138 may be a wound coil, and the second driving unit 125 may be a magnet.

Additionally, a storage space may be formed inside the stator 120, and the mover 130 may be located in this storage space.

In addition, 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, so that the elastic member 140 elastically supports the mover 130. can be supported.

In one embodiment of the present invention, the elastic member 140 includes a first elastic member 143 formed at the bottom of the outer peripheral surface of the mover 130 and a second elastic member formed at the top of the outer peripheral surface of the mover 130 ( 146) may be included.

The elastic member 140 moves the second driving part 125 of the stator 120 and the first driving part 138 of the mover 130 in the up position with the lens of FIG. 2 positioned in the upward direction. When electromagnetic force is not applied, the mover 130 is brought into contact with the upper surface of the base 110.

That is, when the electromagnetic force of the second driving part 125 of the stator 120 and the first driving part 138 of the mover 130 is not applied, the elastic member 140 acts on the mover 130. The mover 130 contacts the upper surface of the base 110 due to its weight.

At this time, the voice coil motor 100 feels that the offset between the upper surface of the mover 130 and the base 110 is approximately 0.03 mm.

Therefore, the camera module of one embodiment of the present invention requires the elastic force of the elastic member 140 and An electromagnetic force greater than the self-weight of the mover 130 is required.

Then, the cover 150 is fixed to the base 110, and the cover 150 surrounds the stator 120 and the movable member 130. Additionally, the cover 150 serves as an upper stopper to stop the mover 130.

Meanwhile, in the present invention, when the lens 135 is in an up position, the mover 130 is in contact with the base 110, and the lens 135 is in a side position or down position. ) In the case of the posture, the mover 130 can be configured to be spaced apart from the base 110.

Additionally, the voice coil motor 100 can be applied as an actuator that drives the lens of a camera module, an actuator driven by piezoelectric force, or a MEMS actuator driven by a capacitive method.

That is, the actuator that drives the lens of the camera module may be one of a voice coil motor (VCM) actuator, an actuator driven by piezoelectric force, or a MEMS actuator driven by a capacitive method.

Here, the camera module may be configured to include a mover 130 including a lens 135, and an actuator that drives the mover 130. At this time, the lens 135 is in an up position. Or, in the case of the side posture, the movable member 130 is in contact with the base 110 that functions as a stopper of the movable member 130, and when the lens 135 is in the down posture, the When the mover 130 is spaced apart from the base 110 or the lens 135 is in an up position, the mover 130 is in contact with the base 110 and the lens 135 ) is in a side position or down position, the mover 130 may be configured to be spaced apart from the base 110.

Therefore, the present invention reduces current consumption by eliminating mechanical offset in the actuator, increases the design freedom of electromagnetic force, and solves the defocus problem by applying current in the opposite direction even when a change in the spring occurs. It has the advantage of being able to improve the yield of the camera module by eliminating the need for initial focusing.

Figure 5 is a graph showing current-distance characteristics according to the posture of a camera module according to an embodiment of the present invention.

First, referring to the graph of FIG. 5, in the “up position” of the camera module, the mover is in contact with the base, and in order for the mover to rise from the base, the elastic force of the elastic member and an electromagnetic force greater than the self-weight of the mover must be applied. As required, more than the standard current must be applied to the driving unit.

Therefore, in FIG. 5, the “up posture” of the camera module has the autofocus search section of the ‘A’ graph.

Therefore, in FIG. 5, the mover is not driven at a current less than the reference current [mA], and the current section below the reference current [mA] can be defined as an undriven section in which the mover is not driven, and this undriven section Since the mover is not driven, autofocus operation is not performed.

And, at a current greater than the reference current [mA], the electromagnetic force driving the mover becomes greater than the self-weight of the mover and the elastic force of the elastic member, and the mover is driven.

Here, the current section above the reference current [mA] can be defined as a driving section in which the mover is driven, and in the operation section, the autofocus operation is performed only because the mover is driven.

In addition, in the "side posture" of the camera module, the mover is in contact with the base, but in order for the mover to rise from the base, the elastic force of the elastic member and the self-weight of the mover are not considered, so a current is applied to the mover. From the moment of doing so, the mover is driven.

Therefore, in the "side posture" of the camera module, there is an autofocus search section of the 'B' graph in FIG. 5.

Here, the voice coil motor arranged in the side position is driven at a smaller current than the voice coil motor arranged in the up position.

In other words, the start current that drives the mover in the side position is smaller than the start current that drives the mover in the up position.

And, in the "side posture" of the camera module, the start current may be 0-10 mA, and the posture difference between the "up posture" and the "side posture" is about 30 ~ It may be 50㎛.

In addition, when the camera module is in the "down position", the mover is spaced away from the base, resulting in the autofocus search section of the 'C' graph in FIG. 5.

Therefore, in the “down position” of the camera module, the mover can be driven in the reverse direction.

As shown in FIG. 4, when the mover 130 is in the down position disposed below the base 110, the elastic member 140 moves the mover 130 in the initial state in which no current is applied to the coil. It can be supported to be placed in a first initial position away from the base 110. When in the down position, when a reverse current is applied to the coil, the mover 130 can move from the first initial position in a direction closer to the base 110.

As shown in FIG. 2, when the mover 130 is in the up position disposed above the base 110, in the initial state in which no current is applied to the coil, the elastic member 140 is held by the mover 130. It can be supported to be placed in a second initial position that is different from the first initial position. When in the up position, when a forward current is applied to the coil, the mover 130 can move from the second initial position in a direction closer to the macro position shown in FIG. 5. Here, the macro position may be an affix position.

As shown in FIG. 5, the distance (D) from the first initial position to the macro position may be longer than the distance (E) from the first initial position to the position in contact with the base 110. As shown in Figure 5, in the macro position the mover can move further in a direction away from the base. That is, in the macro position the movable member may be spaced apart from the cover.

Although embodiments according to the present invention have been described above, they are merely illustrative, and those skilled in the art will understand that various modifications and equivalent scope of embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention should be determined by the following patent claims.

Claims (19)

Base;
a cover disposed on the base;
a mover disposed within the cover; and
It includes a coil and a magnet disposed within the cover and moving the mover along an optical axis,
When no current is applied to the coil, the mover is spaced apart from the base,
A voice coil motor in which a reverse current that moves the mover toward the base is applied to the coil, or a forward current that moves the mover away from the base is applied to the coil. According to paragraph 1,
When a forward current is applied to the coil, the mover moves in a direction closer to the macro position,
A voice coil motor in which the movable member is spaced apart from the cover in the macro position. According to paragraph 1,
The base has a plate shape with an opening through which light passes in the center, and serves as a lower stopper of the mover. According to paragraph 1,
A voice coil motor in which the mover is in contact with the base in an initial state in which no current is applied to the coil when the optical axis is in a side posture disposed parallel to the ground. According to paragraph 1,
The cover is fixed to the base,
A voice coil motor in which the cover serves as an upper stopper of the mover. According to paragraph 1,
When a forward current is applied to the coil, the mover moves in a direction closer to the macro position,
A voice coil motor in which the movable member is spaced apart from the cover in the macro position. According to paragraph 1,
In the initial state in which no current is applied to the coil, the minimum value of the reverse current that moves the mover the longest distance toward the base is smaller than the minimum value of the forward current that moves the mover the longest distance away from the base in the initial state. coil motor. According to paragraph 1,
A voice coil motor including an elastic member coupled to the mover. According to clause 8,
The elastic member includes a first elastic member coupled to an upper part of the mover and a second elastic member coupled to a lower part of the mover. According to clause 8,
When the mover is in a down position positioned below the base, in an initial state in which no current is applied to the coil, the mover is placed in a first initial position away from the base,
A voice coil motor in which, when the mover is in an up position positioned above the base, the mover is placed in a second initial position different from the first initial position in an initial state in which no current is applied to the coil. According to clause 10,
When in the up position, the movable member is in contact with the base in the second initial position. According to clause 10,
A voice coil motor in which the mover moves when a forward current greater than a reference current is applied to the coil in the up position. According to clause 10,
In the up position, the elastic member presses the mover so that an offset exists,
A voice coil motor in which, in the down position, the offset disappears due to deflection due to the self-weight of the mover. image sensor;
The voice coil motor of claim 10; and
A camera module comprising a lens coupled to the mover of the voice coil motor. According to clause 14,
a posture detection sensor that determines one of the up posture and the down posture and outputs posture data; and
A camera module including an image signal processor (ISP) that generates a driving signal for driving the voice coil motor using the posture data output from the posture detection sensor. According to clause 15,
An autofocus algorithm used in the form of an algorithm inside the image signal processor or built into a separate chip from the image signal processor,
The autofocus algorithm detects the focus value of the voice coil motor according to the distance to the subject and outputs a detection signal. According to clause 15,
The posture detection sensor is a camera module including a gyro sensor that detects the direction of gravity. A mobile phone including the camera module of any one of claims 14 to 17. delete