CROSS REFERENCE TO RELATED APPLICATIONS

This application is the National Phase of PCT International Application No. PCT/KR2018/000603, filed on Jan. 12, 2018, which claims priority under 35 U.S.C. 119(a) to Patent Application No. 10-2017-0006224, filed in Republic of Korea on Jan. 13, 2017 and Patent Application No. 10-2017-0046984, filed in Republic of Korea on Apr. 11, 2017, all of which are hereby expressly incorporated by reference into the present application.

TECHNICAL FIELD

The present disclosure relates to a method of applying a driving voltage to a liquid lens, a camera module, and an optical device including the module. More particularly, the present disclosure relates to a method of applying a driving voltage to a liquid lens enabling adjustment of a focal length using electrical energy, a camera module, and an optical device including the module.

BACKGROUND ART

People who use portable devices demand optical devices that have high resolution, are small, and have various photographing functions (an optical zoom-in/zoom-out function, an auto-focusing (AF) function, a handshake compensation or optical image stabilization (OIS) function, etc.). Such photographing functions may be realized by directly moving a plurality of lenses that are combined. In the case in which the number of lenses is increased, however, the size of an optical device may be increased.

The auto-focusing and handshake compensation functions are performed by tilting or moving a lens module including a plurality of lenses, which are fixed to a lens holder in the state in which the optical axes of the lens are aligned, along the optical axis or in a direction perpendicular to the optical axis. An additional lens moving apparatus is used to move the lens module. However, the lens moving apparatus has high power consumption, and an additional cover glass needs to be provided separately from the camera module in order to protect the lens moving apparatus, thus leading to an increase in the overall thickness of an optical device.

Therefore, research has been conducted on a liquid lens configured to electrically adjust the curvature of an interface between two kinds of liquid in order to perform auto-focusing and handshake compensation functions.

DISCLOSURE

Technical Problem

The present disclosure provides a method of applying a driving voltage to a liquid lens, which enables improvement of auto-focusing resolution without an increase in power consumption, a camera module, and an optical device including the module.

However, the objects to be accomplished by the disclosure are not limited to the above-mentioned objects, and other objects not mentioned will be clearly understood by those skilled in the art from the following description.

Technical Solution

In one embodiment, a camera module may include a first plate including a cavity formed therein to accommodate a conductive liquid and a non-conductive liquid, an electrode unit disposed on the first plate and electrically connected to an external power source to change an interface between the conductive liquid and the non-conductive liquid, an insulation unit disposed on the electrode unit to prevent contact with the non-conductive liquid, and a control unit controlling a voltage applied to the electrode unit. The electrode unit may include a first electrode and a second electrode electromagnetically interacting with each other to change the interface between the conductive liquid and the non-conductive liquid, the first electrode may include a plurality of electrode sectors arranged sequentially in a clockwise direction with respect to an optical axis, and the control unit may perform control so as to apply voltages to driving electrodes corresponding to the electrode sectors by rotation in a clockwise direction or in a counterclockwise direction.

Depending on the embodiment, the control unit may apply a first voltage to at least one of the driving electrodes, and may apply a second voltage, which has a different intensity from the first voltage, to remaining ones of the driving electrodes.

Depending on the embodiment, the second voltage may be higher than the first voltage.

In another embodiment, a method of applying a voltage to a liquid lens may include applying a first voltage to each of 1stto nth(n being an integer of 2 or greater) driving electrodes, applying a second voltage to m (m being an integer of 1 to n−1) driving electrodes of the 1stto nthdriving electrodes and applying a first voltage to remaining n-m driving electrodes, and applying the second voltage to each of the 1stto nthdriving electrodes. The applying the second voltage to m driving electrodes of the 1stto nthdriving electrodes and applying the first voltage to remaining n-m driving electrodes may include applying m driving voltages as the second voltage by rotation.

Depending on the embodiment, the second voltage may be the sum of the first voltage and a unit voltage of a voltage driver supplying a driving voltage to the liquid lens.

Depending on the embodiment, in the applying m driving voltages of the 1stto nthdriving voltages as the second voltage, n sub-cycles may be provided, and at least one of the 1stto nthdriving voltages may be changed in adjacent ones of the n sub-cycles.

In still another embodiment, a liquid lens may include a conductive liquid and a non-conductive liquid accommodated in a cavity so as to form an interface therebetween, and 1stto nth(n being an integer of 2 or greater) driving electrodes configured to control the interface. 1stto nthdriving voltages respectively applied to the 1stto nthdriving electrodes may be controlled in respective cycles, each of which includes n sub-cycles. In each of the n sub-cycles, at least one of the 1stto nthdriving voltages may be applied as a first voltage, m (m being an integer of 1 to n−1) driving voltages of the 1stto nthdriving voltages may be applied as a second voltage, and the m driving voltages may be applied as the second voltage by rotation.

Depending on the embodiment, the second voltage may be the sum of the first voltage and a unit voltage of a voltage driver supplying a driving voltage to the liquid lens.

Depending on the embodiment, any one of the 1stto nthdriving voltages may be applied as the second voltage in the m sub-cycles.

Depending on the embodiment, at least one of the 1stto nthdriving voltages may be changed in adjacent ones of the n sub-cycles.

Depending on the embodiment, the sum of the 1stto nthdriving voltages applied in each of the n sub-cycles may be maintained at a constant level.

In still another embodiment, an optical device may include the camera module described above, a display unit outputting an image, a battery supplying power to the camera module, and a housing in which the camera module, the display unit, and the battery are mounted.

In still another embodiment, a liquid lens may include a conductive liquid and a non-conductive liquid accommodated in a cavity so as to form an interface therebetween, and n (n being an integer of 2 or greater) individual electrodes and a common electrode configured to control the interface. A first driving voltage, which is applied between the common electrode and any one of the n individual electrodes, may be controlled in respective unit cycles, each of which includes a first sub-cycle and a second sub-cycle. The level of the first driving voltage in the first sub-cycle may be a first voltage, and the level of the first driving voltage in the second sub-cycle may be a second voltage.

Depending on the embodiment, the sum of the number of the first sub-cycles and the number of the second sub-cycles may be X (X being an integer of 2 or greater).

Depending on the embodiment, in one unit cycle, the sum of the driving voltages applied between the n individual electrodes and the common electrode in each of the sub-cycles may be maintained at a constant level.

Depending on the embodiment, if the number of the second sub-cycles of the X sub-cycles is Y in one unit cycle, the average driving voltage in the unit cycle may satisfy the following equation.
Average Driving Voltage in Unit Cycle=First Voltage+(Predetermined Unit Driving Voltage*Y)/X(Equation)

Here, Predetermined Unit Driving Voltage=Second Voltage−First Voltage

Depending on the embodiment, when the process goes from the first sub-cycle to the second sub-cycle, which is adjacent to the first sub-cycle, the level of the driving voltage applied to at least one of the n individual electrodes may be changed.

Depending on the embodiment, the second voltage may be the sum of the first voltage and the predetermined unit voltage.

Depending on the embodiment, the first driving voltage may have two voltage levels.

Depending on the embodiment, the second voltage may be higher than the first voltage.

In still another embodiment, a camera module may include a liquid lens, which includes a conductive liquid and a non-conductive liquid accommodated in a cavity so as to form an interface therebetween and n (n being an integer of 2 or greater) individual electrodes and a common electrode configured to control the interface, and a control circuit controlling a voltage applied to the n individual electrodes and the common electrode. A first driving voltage, which is applied between the common electrode and any one of the n individual electrodes, may be controlled in respective unit cycles, each of which includes a first sub-cycle and a second sub-cycle. The level of the first driving voltage in the first sub-cycle may be a first voltage, and the level of the first driving voltage in the second sub-cycle may be a second voltage.

In still another embodiment, an optical device may include a camera module, a display unit outputting an image, a battery supplying power to the camera module, and a housing in which the camera module, the display unit, and the battery are mounted.

The above aspects of the present disclosure are only a part of the exemplary embodiments of the present disclosure, and various embodiments based on technical features of the present disclosure may be devised and understood by those skilled in the art from the following detailed description of the present disclosure.

Advantageous Effects

The effects of the device according to the present disclosure will be described below.

According to a method of applying a driving voltage to a liquid lens, a camera module, and an optical device including the module according to an embodiment, it is possible to increase auto-focusing resolution using a unit voltage within a constant output voltage range of a voltage driver.

In addition, an increase in the output voltage range of a voltage driver is not required while increasing auto-focusing resolution, thus leading to a reduction in the amount of power consumed by an optical device.

However, the effects achievable through the disclosure are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the following description.

