KR20180045078A - Cleaning device using electrowetting and method of removing droplet on the same - Google Patents

Abstract

Disclosed are a cleaning device using electrowetting and a method of removing a droplet therein. The cleaning device comprises a base layer and an electrode arranged on the base layer. A surface of the cleaning device tilts in a gravitational direction. As a specific voltage is applied to the electrode, a droplet attached on the surface of the cleaning device vibrates. According to the vibration, the droplet moves in the gravitational direction so that the droplet is removed from the cleaning device.

Description

TECHNICAL FIELD [0001] The present invention relates to a cleaning apparatus using electrowetting and a droplet removing method therefor. BACKGROUND ART [0002]

The present invention relates to a cleaning apparatus using electrowetting and a droplet control method therefor.

The camera and other devices are exposed to the external environment. Therefore, in the case of rain, when water is wet, water adheres to the camera surface. In this case, since there is no separate function for removing the water, the camera performance is inevitably lowered.

KR 10-1653807 B

The present invention provides a cleaning device using electrowetting and a droplet removing method therefor.

According to an aspect of the present invention, there is provided a cleaning apparatus comprising: a base layer; And an electrode arranged on the base layer. Here, the surface of the cleaning device is inclined in the direction of gravity. As a specific voltage is applied to the electrode, the droplet attached to the surface of the cleaning device vibrates, and the droplet moves in the gravity direction The droplet is removed from the cleaning device.

According to another aspect of the present invention, there is provided a cleaning apparatus including: a vibrating unit for vibrating a liquid droplet attached to a surface of the cleaning apparatus to reduce an adhesion force between the liquid droplet and a surface of the cleaning apparatus; And a control unit for controlling the operation of the vibrating unit. Here, the surface of the cleaning device is inclined in the direction of gravity, and the droplet moves in the gravity direction in accordance with the vibration to remove the droplet from the cleaning device.

A cleaning device according to another embodiment of the present invention includes a vibrating part for vibrating a droplet attached to a surface of the cleaning device to reduce the adhesion of the droplet and the surface of the cleaning device. The vibrating part has a specific pattern. Here, the surface of the cleaning device is inclined in the direction of gravity, and the droplets of the pattern are the same as the direction of movement of the droplet, so that the droplet moves along the droplet.

A cleaning device according to another embodiment of the present invention includes a vibrating part for vibrating a droplet attached to a surface of the cleaning device to reduce the adhesion of the droplet and the surface of the cleaning device. Here, the surface of the cleaning apparatus has a structure in which, when the droplet moves according to the vibration, the change in the contact angle of the droplet in the moving direction is larger than the change in the contact angle of the droplet in the direction opposite to the moving direction.

According to an embodiment of the present invention, there is provided a method of removing droplets from a cleaning apparatus, the method comprising: applying a specific voltage to an electrode according to a user command to vibrate droplets adhering to a surface of the cleaning apparatus; And moving the droplet in the gravitational direction in response to the vibration. Here, the surface of the cleaning device is inclined in the direction of gravity, and when the droplet moves according to the vibration, the change in the contact angle of the droplet in the movement direction is larger than the change in the contact angle of the droplet in the direction opposite to the movement direction .

The cleaning device according to the present invention removes droplets on the surface by using electro-wetting, so that droplets can be removed quickly and efficiently.

In addition, since the electrode of the cleaning apparatus is the same as the moving direction of the droplet, the removal speed of the droplet becomes faster and the voltage applied to the electrode may be lowered.

1 is a view illustrating a droplet removing process of a cleaning apparatus according to an embodiment of the present invention.
FIG. 2 is a view showing a schematic structure of a cleaning apparatus according to an embodiment of the present invention.
3 is a view illustrating an electrode pattern according to an embodiment of the present invention.
4 is a view showing a flow of a droplet upon drop removal according to an embodiment of the present invention.
FIG. 5 is a graph showing a change in the droplet contact angle upon removing a droplet according to an embodiment of the present invention.
6 is a diagram showing the results of the droplet removal experiment.
7 is a view schematically showing an electrode of a cleaning device according to another embodiment of the present invention.

As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. In this specification, the terms "comprising ", or" comprising "and the like should not be construed as necessarily including the various elements or steps described in the specification, Or may be further comprised of additional components or steps. Also, the terms "part," " module, "and the like described in the specification mean units for processing at least one function or operation, which may be implemented in hardware or software or a combination of hardware and software .

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a cleaning device capable of self-cleaning droplets such as rainwater, mist, and the like, and a droplet removing method therefor. The cleaning device may be a single device or a device coupled to another device.

According to one embodiment, the cleaning device may be an appliance including an external glass, such as a camera of a vehicle, a digital camera, a mobile camera, an image sensor of the Internet of things, and the like. Of course, the cleaning device is not limited to a camera but includes all the devices for which a droplet needs to be removed.

Such a cleaning apparatus is exposed to the external environment, and as a result, droplets such as rainwater can be attached to the surface of the cleaning apparatus.

Conventionally, when rainwater or the like adheres to a glass surface of a camera or the like, there is no way to remove rainwater or the like, and thus the performance of the camera has been inevitably degraded. In particular, in the case of a vehicle that controls a specific function of the vehicle based on the image of the camera, a drop in image quality due to droplets may cause a vehicle accident.

Accordingly, it is necessary to remove the droplet as soon as the droplet adheres to the surface, and the present invention proposes a cleaning device capable of removing the droplet immediately when the droplet adheres to the surface.

According to one embodiment, the cleaning apparatus removes droplets using an electrorowetting technique. In particular, the cleaning apparatus can remove droplets on the surface by applying a specific voltage to the electrodes.

In another aspect, the cleaning apparatus can generate vibration on the surface to remove droplets. When vibration is generated on the surface of the cleaning device, the adhesion force between the droplet and the surface is weakened, so that the droplet can be moved and removed in the gravity direction. For example, the surface of a cleaning device, such as a vehicle camera, is tilted in the direction of gravity, so that when the adhesion between the droplet and the surface is weakened, the droplet moves in the direction of gravity by gravity, It can be removed from the cleaning device and removed.

From the point of view of vehicle control, rain can be attached to the surface of the camera as it rains. In this case, when the driver inputs the rainwater removal command (droplet removal command), the control unit (not shown) can apply the specific voltage to the electrode formed on the surface of the camera to remove the rainwater. The specific voltage may be supplied to the camera from a power source, for example a battery of the vehicle. On the other hand, the controller may be one of electronic control units (ECU) of a charge amount.

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

FIG. 1 is a view showing a droplet removing process of a cleaning device according to an embodiment of the present invention. FIG. 2 is a schematic view illustrating a cleaning device according to an embodiment of the present invention. FIG. 3 is a view showing an electrode pattern according to an embodiment of the present invention, and FIG. 4 is a view illustrating a flow of a droplet upon drop removal according to an embodiment of the present invention. FIG. 5 is a view showing a change in a droplet contact angle upon dropping a droplet according to an embodiment of the present invention, and FIG. 6 is a diagram showing a droplet removal experiment result.

1 shows a surface change of a camera as a cleaning device of the present invention. As shown in FIG. 1, when a specific voltage is applied to the electrode when a liquid droplet is attached to the surface of the camera, the droplet of the cleaning area of the camera surface is removed as shown in the right image, Loses. Here, the cleaning region is a region required for photographing, and can correspond to the lens portion.

A cleaning apparatus for removing such a droplet, particularly a portion of the cleaning apparatus corresponding to the cleaning region, may have the structure of FIG.

2, the cleaning apparatus of this embodiment may include a base layer 200, an electrode 202, an insulating layer 204, and a hydrophobic layer 206.

The base layer 200 may be a cover glass that protects the cleaning device from external contamination and impact, for example, and may be disposed on a lens portion (not shown).

According to one embodiment, the base layer 200 may be non-wet glass.

The electrode 202 may be a transparent electrode made of, for example, ITO or the like, and may be formed on the base layer 200 with a predetermined pattern.

According to one embodiment, the electrode 202 may include a first electrode 300 of a comb structure and a second electrode 302 of a comb structure, as shown in FIG.

The first electrode 300 may include a first base pattern 310 and at least one first branch pattern 312.

A portion of the first base pattern 310 is electrically coupled to the power source 208 or to ground and a specific voltage is applied to the first base pattern 310 from the power source or the ground. On the other hand, the power source 208 may be located inside or outside the cleaning apparatus.

The first branch pattern 312 is formed to extend from the first base pattern 310 in a direction intersecting with the first base pattern 310, preferably in the vertical direction. As a result, when a specific voltage is applied to the first base pattern 310, a specific voltage is also supplied to the first branch pattern 312.

According to one embodiment, the first branch patterns 312 extend from the first base pattern 310, and the spacing between the first branch patterns 312 may be the same. Of course, some of the intervals between the first branch patterns 312 may be different as long as the first branch patterns 312 and the second branch patterns 320 intersect.

The second electrode 302 may include a second base pattern 322 and at least one second branch pattern 320.

A portion of the second base pattern 322 is electrically connected to the power source 208 or ground and a specific voltage is applied to the second base pattern 322 from the power source 208 or the ground.

The second branch pattern 320 is formed to extend from the second base pattern 322 in a direction intersecting with the second base pattern 322, preferably in the vertical direction. As a result, when a specific voltage is applied to the second base pattern 322, a specific voltage is also supplied to the second branch pattern 320.

In addition, the second branch patterns 320 are arranged to cross the first branch patterns 312 as shown in FIG. However, the first branch patterns 312 and the second branch patterns 320 may be physically separated.

According to one embodiment, the second branch patterns 320 may extend from the second base pattern 322 and the spacing between the second branch patterns 320 may be the same. Of course, some of the intervals between the second branch patterns 320 may be different as long as the first branch patterns 312 and the second branch patterns 320 intersect.

Meanwhile, in order to generate vibration on the surface of the cleaning apparatus, a first voltage may be applied to one of the first electrode 300 and the second electrode 302, and a second voltage lower than the first voltage may be applied to the other electrode . Here, the first voltage may be a positive voltage and the second voltage may be a ground voltage.

Referring again to FIG. 2, the insulating layer 204 is arranged over the electrode 202 and can fill the gap between the electrodes 300 and 302.

According to one embodiment, the insulating layer 204 may comprise at least one material selected from the group consisting of ferrolein C, Teflon, and a metal oxide film.

The hydrophobic layer 206 is formed on the insulating layer 204 and may be made of a material having a low affinity for a fluid such as water. As a result, the droplet can easily move from the surface of the hydrophobic layer 206.

Let's take a look at the cleaning operation in a cleaning device having this structure.

For example, when the user inputs a droplet removal command, the power source 208 applies a first voltage to one of the electrodes 300 and 302 under the control of the control unit, Voltage is applied. As a result, the droplet adhering to the surface of the cleaning apparatus vibrates.

As the surface of the cleaning device vibrates, the adhering force between the surface and the droplet decreases. In this case, since the surface of the cleaning device is inclined in the direction of gravity, the droplet adhered to the surface slips in the gravity direction as shown in FIG. 4 and is released from the cleaning device. That is, the droplet is removed from the cleaning device.

Particularly, since the cleaning device of this embodiment uses the electrowetting technique, the droplet removal time is quick and efficient.

According to one embodiment, the change of the contact angle in the direction opposite to the moving direction of the droplet and the direction of movement in the droplet vibration may be different from the change in the contact angle in the other direction. This difference can be useful for slipping droplets. In addition, due to the difference in the contact angle, the droplet can be removed by sliding in the gravitational direction despite the low inclination of the surface of the cleaning apparatus.

According to another embodiment, the electrodes 300 and 302 have a comb shape, and the combs of the branch patterns 312 and 320 can be formed in the gravitational direction. As a result, when the liquid droplet vibrates due to the specific voltage, the change in the contact angle of the liquid droplet becomes large in the direction of the solid lines of the branch patterns 312 and 320 as shown in FIG.

That is, the direction in which the droplet slides coincides with or is similar to the direction of the droplets in the electrodes 300 and 302, and as a result, the droplet slips more easily during droplet vibration. Therefore, even if a lower voltage is applied to the electrodes 300 and 302, the droplet can be easily removed.

From another point of view, if the change in the contact angle of the liquid droplet in the direction in which the liquid droplet slides, i.e., in the gravity direction, is greater than the change in the contact angle in the other direction, the liquid droplet can be easily removed.

Hereinafter, actual experimental results will be described.

As shown in FIG. 6, droplets (rainwater) on the surface of the camera to which the cleaning device is applied are removed as shown in FIG. 6 as a result of mounting the general camera and the camera of the present invention on a rainy day, It can be confirmed that the image is taken more clearly.

7 is a view schematically showing an electrode of a cleaning device according to another embodiment of the present invention. However, only one electrode is shown because the electrodes are the same in structure but different in arrangement direction. Of course, the branches of the electrodes may be arranged to cross each other.

Referring to FIG. 7, one of the electrodes may include a base pattern 700 and at least one branch pattern 702.

The branch pattern 702 may include at least one protrusion 712 protruding from the branch portion 710 and the branch portion 710. That is, unlike the branch pattern of FIG. 3, the branch pattern 702 of the present embodiment may include at least one protrusion 712. When such protrusion 712 is formed, the entire surface area of the electrode can be widened.

Of course, the branch patterns of the electrodes may be arranged crossing each other similarly to the branch patterns of Fig.

In addition to the cleaning apparatuses of the above embodiments, the structure of the cleaning apparatus can be variously modified as long as the cleaning apparatus can remove droplets.

According to one embodiment, the cleaning device may include a vibrating part for vibrating a droplet attached to the surface to reduce the adhering force of the droplet and the surface of the cleaning device. The vibrating part has a specific pattern. Further, the surface of the cleaning device is inclined in the direction of gravity, and the droplets of the pattern are the same as the moving direction of the droplet, so that the droplet can move along the droplet.

Of course, the change in the contact angle of the liquid droplet in the direction opposite to the movement direction and the movement direction may be larger than the change in contact angle in the other direction according to the vibration.

According to another embodiment, the cleaning device may include a vibrating part that vibrates the droplet attached to the surface of the cleaning device to reduce the adhering force of the droplet and the surface of the cleaning device. Here, the surface of the cleaning apparatus has a structure such that when the liquid droplet moves in accordance with the vibration, the change in the contact angle of the liquid droplet in the moving direction or the direction opposite to the moving direction is larger than the change in the contact angle of the liquid droplet in the other direction .

Meanwhile, the vibrating portion includes an electrode, and the result of the electrode may be the same as the moving direction of the droplet.

It will be apparent to those skilled in the art that various modifications, additions and substitutions are possible, without departing from the spirit and scope of the invention as defined by the appended claims. Should be regarded as belonging to the following claims.

200: base layer 202: electrode
204: insulating layer 206: hydrophobic layer
300: first electrode 302: second electrode
310: first base pattern 312: first branch pattern
322: second base pattern 320: second branch pattern

Claims (18)

In the cleaning device,
Base layer; And
And an electrode arranged on the base layer,
The surface of the cleaning device is inclined in the direction of gravity. As the specific voltage is applied to the electrode, the droplet attached to the surface of the cleaning device vibrates, and the droplet moves in the gravity direction according to the vibration, And the liquid droplet is removed from the apparatus. The cleaning apparatus according to claim 1, wherein the change in the contact angle of the liquid droplet in the moving direction and the direction opposite to the moving direction of the liquid droplet is greater than the change in the contact angle in the other direction. 3. The cleaning apparatus according to claim 2, wherein the texture of the electrode coincides with the moving direction. The method of claim 1, wherein the electrode comprises a first electrode and a second electrode,
Wherein the first electrode has first base patterns and first branch patterns extending in a direction intersecting the first base pattern and extending from the first base pattern and the second electrode has a second base pattern and a second base pattern, Having second branch patterns extending in length from the second base pattern in a direction crossing the base pattern,
Wherein the first branch patterns and the second branch patterns cross each other. 5. The cleaning apparatus according to claim 4, wherein a combination of the first branch patterns and the second branch patterns is the same as the moving direction of the droplet. The cleaning apparatus according to claim 4, wherein a positive voltage is applied to the first electrode and a ground voltage is applied to the second electrode. The method according to claim 1,
An insulating layer arranged on the electrode; And
And a hydrophobic layer arranged on the insulating layer,
Wherein the droplets are positioned on the hydrophobic layer. The cleaning device according to claim 1, wherein the cleaning device is an image sensor of a camera, a digital camera, a mobile camera, or an object Internet of a vehicle, and the base layer is glass. The cleaning apparatus according to claim 1, wherein the power source for supplying the specific voltage to the electrode is located outside the cleaning apparatus. In the cleaning device,
A vibrating unit for vibrating a liquid droplet attached to a surface of the cleaning device to reduce an adhesion force between the liquid droplet and a surface of the cleaning device; And
And a control unit for controlling the operation of the vibrating unit,
Wherein a surface of the cleaning device is inclined in a gravitational direction and the droplet moves in the gravity direction according to the vibration to remove the droplet from the cleaning device. 11. The cleaning apparatus according to claim 10, wherein the change in the contact angle of the liquid droplet in the moving direction and the direction opposite to the moving direction of the droplet is greater than the change in the contact angle in the other direction. 11. The cleaning device according to claim 10, wherein the texture of the oscillating portion coincides with the moving direction. The cleaning device according to claim 10, wherein the vibrating part is arranged on a lens part of the camera. In the cleaning device,
And a vibrating part for vibrating a liquid droplet attached to the surface of the cleaning device to reduce the adhesion of the liquid droplet and the surface of the cleaning device,
The vibrating part has a specific pattern,
Wherein a surface of the cleaning device is inclined in a gravitational direction, and the shape of the pattern is the same as the direction of movement of the droplet, so that the droplet moves along the texture. 15. The cleaning apparatus according to claim 14, wherein a change in the contact angle of the liquid droplet in the direction opposite to the movement direction and the movement direction according to the vibration is larger than a change in the contact angle in the other direction. In the cleaning device,
And a vibrating part for vibrating the droplet attached to the surface of the cleaning device to reduce the adhesion of the droplet and the surface of the cleaning device,
The surface of the cleaning device has a structure such that the change in the contact angle of the liquid droplet in the direction opposite to the movement direction and the movement direction when the liquid droplet moves according to the vibration is larger than the change in contact angle of the liquid droplet in the other direction Cleaning device. 17. The apparatus of claim 16, wherein the vibrating portion includes an electrode,
Wherein a shape of the electrode is the same as a moving direction of the droplet. Applying a specific voltage to the electrode according to a user command to vibrate the droplet adhering to the surface of the cleaning apparatus; And
And moving the droplet in a gravitational direction in response to the vibration,
Wherein a surface of the cleaning device is inclined in a gravitational direction and a change in the contact angle of the liquid droplet in a direction opposite to the movement direction and the movement direction when the liquid droplet moves according to the vibration is larger than a change in contact angle of the liquid droplet in the other direction And removing the droplets from the cleaning device.

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