KR20060100314A - Vibration prevention control method for driving unit in optics driver device - Google Patents

Abstract

The present invention relates to a dustproof control method of a drive unit of an optical drive device, and includes a primary current change step of changing a current to start driving a drive unit formed in an optical drive device, and an intrinsic vibration of the drive unit after the primary current change step. An optical drive device driver comprising a current holding step that does not change the amount of current for a period of half the period and a second current changing step of changing the current by the same amount of current change as the first current changing step after the current holding step. Provides a dustproof control method.

The present invention provides a method of applying a secondary current change amount having a phase difference of 180 degrees after applying a primary current change amount corresponding to 1/2 of a required current change amount for moving a focus lens. By vibrating the vibration of the drive unit, the image collected by the image sensor can be prevented from shaking due to the vibration generated after the movement of the focus lens in the camera module, so that a clear image can be taken. By shortening the time of the focus shift image acquisition process of the camera has the advantage that can shorten the overall shooting time.

Vibration, Dustproof, Active Vibration Control

Description

VIBRATION PREVENTION CONTROL METHOD FOR DRIVING UNIT IN OPTICS DRIVER DEVICE}

1 is an exploded perspective view showing an optical drive device.

2 is a cross sectional front view showing the optical drive device.

3 is a simplified view of a motion model of the optical drive unit.

4 is a diagram showing a vibration generated in the conventional drive unit.

5 is a diagram illustrating a dustproof process according to the present invention.

6 is a diagram showing the vibration of the drive unit according to the present invention.

* Description of the major symbols for the main parts of the drawings *

1: lens assembly 2: upper housing

4: spring 5: upper soft magnetic material

6: permanent magnet 7: lower soft magnetic material

8: coil 9: holder

11 connector 12 lower housing

50: optical drive device

The present invention relates to a dustproof control method of a driving unit of an optical driving device, and in particular, to prevent vibration of a focus lens generated when an optical driving device mounted on a small camera module is operated, thereby rapidly collecting a clear image, thereby capturing the entire shooting time of the camera module. The present invention relates to a dustproof control method of a driving unit of an optical driving apparatus capable of capturing a clear image while shortening the speed.

In general, the automatic focusing device of a lens used in a digital camera uses a method of linearly moving a focus lens in an optical axis direction using a converting device such as a gear to rotate a stepping motor or a DC motor.

However, the auto focusing device of small lenses used in limited spaces such as camera modules of mobile phones makes it difficult to install rotary motors and gearboxes, so many linear actuators can be used to linearly move the focus lens without a converting device. .

As shown in FIGS. 1 and 2, the general optical driving device 50 has a vertical linear motion of a driving unit consisting of a coil 8, a holder 9, and a connector 11 having a focus lens mounted thereon. When current flows, it is generated by the magnetic force (Fleming's left-hand law) formed in the coil 8 formed in the drive section in the vertical direction.

That is, when the magnetic flux generated in the permanent magnet 6 flows to the upper and lower soft magnetic bodies 5 and 7 forming the magnetic circuit, a constant magnetic flux always flows in the gap between the upper and lower soft magnetic bodies 5 and 7. do.

At this time, when a current is applied by applying a voltage to the coil 8 located in the gap, the current is connected to the magnetic flux, and a magnetic force in the vertical direction is generated. When the magnetic force is increased by increasing the current, the driving unit of the driving device is a spring (4). The elastic restoring force of) is gradually moved upwards, and when the current supply to the coil 8 is stopped, the magnetic force disappears and the driving unit is returned to its initial position by the elastic restoring force of the spring 4 of the optical drive device. .

In this case, when the current is inputted into the coil 8 to operate the driving unit coupled to the spring 4, the driving unit coupled to the spring 4 generates a vibration having a predetermined period.

This is because the optical drive device 50 is a non-attenuated 1 degree of freedom in which the damping component is coupled to the spring 4 between the drive unit including the focus lens and the device housings 2 and 12, so that vibration of the drive unit is generated for a long time. to be.

In detail, the driving unit of the optical driving device 50 is fixed to the housings 2 and 12 by the spring only 4 so that the motion model of the driving unit can be simply expressed as shown in FIG. 3.

Referring to FIG. 3, the driving part formed in the optical driving device 50 is an undamped 1 degree of freedom without attenuation, and m shown in FIG. 3 is the mass of the driving part including a lens, and k ₁ , k ₂ is the spring constant of the spring holding the drive, F _m is the magnetic force generated by the drive, and F _g is the self-weight due to the mass of the drive.

The equation of motion of the drive unit fixed to the housings 2 and 12 by the spring 4 alone may be defined by the following equation.

In addition, the frequency and period of the vibration generated in the non-damping 1 degree of freedom meter is determined by the natural frequency as shown below, and the weight and the spring constant of the drive unit are always constant, so the frequency and period of the vibration occurring for any type of input Becomes constant.

As described above, since the optical driving device is a non-attenuating 1 degree of freedom without attenuation components, when a current is input to the optical driving device to focus the image of the camera module, vibration is generated in the driving unit for a long time as shown in FIG. 4. have.

Due to the above phenomenon, the focus lens included in the driving unit vibrates up and down while collecting an image from the image sensor of the camera module. As a result, a vibration phenomenon of the collected image occurs, thereby making it impossible to collect images. Therefore, since image collection of the image sensor is possible only after the vibration of the focus lens disappears, much time is required for the focus shift image acquisition process of collecting the image after moving the focus lens with the optical driving device.

In particular, the camera module requires a plurality of times the focus shift image acquisition process to shoot by using the autofocus control function, there is a problem that the total shooting time of the camera module is very long when vibration of the focus lens occurs.

The present invention for solving the above problems has a phase difference of 180 degrees after applying the first current change amount corresponding to 1/2 of the required current change amount required to move the focus lens to the same value as the first current change amount 2 By vibrating the vibration of the driving unit by the method of applying the difference current difference, the optical driving unit driver can capture a clear image by preventing the image collected by the image sensor from shaking due to the vibration generated after the movement of the focus lens in the camera module. Its purpose is to provide a dustproof control method.

Another object of the present invention is to provide an anti-vibration control method of the optical driving device driver that can shorten the overall shooting time of the camera module by reducing the time of the focus shift image acquisition process required for the automatic focusing of the camera module. have.

In order to achieve the above object, the optical drive device dustproof control method according to the present invention includes a primary current change step of changing a current to operate a drive unit formed in the optical drive device and an optical drive device from the primary current change step. The branch includes a current holding step of maintaining a current amount for a time equal to 1/2 of the natural vibration period, and a second current changing step of changing a current by the same amount of current change as the first current changing step after the current holding step.

In this case, it is preferable to apply the current change amount in the first current change step to a value corresponding to 1/2 of the total current change amount required to move the driving unit.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

According to the present invention, when the first vibration source generated in the vibration system (or sound level meter) is supplied to the vibration system, another disturbance (second disturbance) having the same amplitude as the original vibration source and having a phase difference of 180 degrees is first generated. It is based on the Active Control of Noise and Vibration technology that the vibration value generated by canceling the vibration becomes zero.

In order to apply the above theory, a disturbance drive source that generates other disturbances having the same amplitude as the original vibration source and having a phase difference of 180 degrees is required. However, since a separate disturbance drive source cannot be added to the optical drive device, it is necessary to move the drive unit. Instead of applying the current change amount at one time, the current change amount corresponding to 1/2 of the required current change amount is applied firstly, and the current is maintained for 1/2 hour (180 degrees phase difference) of the natural vibration period generated in the driving part. Active noise and vibration control technology is applied to the optical drive system by applying the current change amount corresponding to 1/2 of. That is, comparing the present invention with the theory, the first current change step of the present invention corresponds to the first vibration source of the theory, the current holding step corresponds to a phase difference of 180 degrees, and the second current change step is different for the vibration cancellation of the theory. It is a disturbance.

In order to achieve the present invention based on the above theory, first, a current change amount is first applied so that an initial operation of a driving unit formed in the optical drive device can be made. (Primary current change step (S10))

At this time, the primary current change amount is a change amount corresponding to 1/2 of the current change amount required for the required movement amount of the driving unit, and the driving unit starts moving by the primary current change amount.

After that, the current is kept constant without change until the half point of the natural vibration period of the driving unit (current holding step (S20)).

Then, when the amount of current applied in the first current change step (S10) is maintained to a point of 1/2 of the natural vibration period in a constant state, as shown in Figure 5, the drive unit of the optical drive device The driving unit moves along the first waveform A of the first vibration curve having the natural oscillation period of the driving unit.

Here, the natural vibration and the natural period of the vibration generated in the drive unit is calculated by the formula specified below.

The natural oscillation period value according to the above formula is calculated based on the theory, and in actual application, it is difficult to accurately obtain the weight and spring constant value of the driving part affecting the natural oscillation period. It is preferable to determine the holding time of the current holding step (S20) by accurately measuring.

After the current holding step, the same current change amount as the first current change step is applied to the optical drive device. (Second Current Change Step (S30))

Then, as shown in FIG. 5, the second vibration having the same vibration period and the same amplitude occurs at the highest point of the first waveform of the first vibration curve generated when the first current change amount is applied.

Therefore, as shown in FIG. 6, after the first vibration curve generated in the primary current change step and the secondary vibration curve generated in the secondary current change step cancel each other to become 1/2 of the natural vibration period (after holding time) ), The vibration generated in the driving unit of the optical driving device is removed.

On the other hand, the amount of movement of the driving unit is determined by the amount of current flowing through the coil, but in the control of the general optical driving device, the amount of current is controlled by using a voltage input to the input terminal of the driving transistor without directly controlling the amount of current. In this case, the voltage used as the control input is expressed as a formula below.

Where ΔV is the required voltage change, ΔV1 is the primary voltage change, ΔV2 is the secondary voltage change, and Td is the holding time between the primary and secondary voltage changes.

As a result, in order to prevent vibration generated in the driving unit, after forming a primary vibration by applying a voltage as much as a primary voltage change amount corresponding to 1/2 of the required voltage change amount required for the required movement amount of the driving unit, the primary vibration and Maintaining the voltage for a time equal to 1/2 of the natural oscillation period so as to have a phase difference of 180 degrees, and applying the same voltage change amount as the first voltage change amount in the second order, the first wave having the phase difference and the phase difference is 180 degrees And the secondary wave cancel each other out so that the driving unit can oscillate vibration generated at the step input.

Although the above-described embodiments have been described with respect to the most preferred examples of the present invention, it is not limited to the above embodiments, and various modifications are possible within the scope without departing from the technical spirit of the present invention. It is evident to those who have knowledge of.

As described above, the optical control device driver dustproof control method of the present invention has a phase difference of 180 degrees after applying a primary current change corresponding to 1/2 of the required current change required to move the focus lens, and has a primary current change amount. By vibrating the driving part by applying the secondary current change amount to the same value as, by avoiding the shaking of the image collected by the image sensor due to the vibration generated after the movement of the focus lens in the camera module to capture a clear image There is an advantage.

By doing so, the entire focusing time of the camera module can be shortened by shortening the time of the focus shift image collection process required for the automatic focusing of the camera module.

Claims (2)

In the dustproof control method of the drive unit of the optical drive device capable of dust-proof vibration generated during operation of the drive unit formed in the optical drive device, A primary current changing step of changing a current to start driving of a driving unit formed in the optical driving device; A current holding step of changing the amount of current for a time equal to 1/2 of the natural vibration period of the driving unit after the first current changing step; And a secondary current change step of changing a current by the same amount of current change as the first current change step after the current holding step. The dustproof control of the driving unit of claim 1, wherein the amount of current that changes in the first current change step changes the current to a value equal to 1/2 of the required current change required to move the focus lens. Way.

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