JP6163370B2 - Imaging apparatus and water droplet removal method - Google Patents

Description

  The present invention relates to an imaging device used outdoors and a water droplet removal method for removing water droplets attached to a lens of the imaging device.

In general, an imaging device such as a vehicle-mounted camera is often attached outside the vehicle (outside). For this reason, raindrops and dirt may adhere to the surface of the lens of the camera due to the weather and the surrounding environment, and the photographed image may become unclear. In particular, in a vehicle-mounted camera attached to the rear of the vehicle body, water droplets containing dirt are likely to adhere to the surface of the lens of the vehicle-mounted camera due to splash (rolling up) due to traveling of the vehicle when it is raining. For this reason, it has been experimentally known that water droplets adhering to the surface of the lens dries later and dirt remains on the lens surface.
For this reason, techniques for removing water droplets adhering to the surface of the lens have been proposed. For example, Patent Document 1 discloses a technique for removing water droplets and dirt on a glass surface by spraying air or water generated by a compressed air generating unit at a high pressure on the glass on the front surface of the camera. Further, in Patent Document 2, a circular housing glass is arranged in front of the camera, the housing glass is rotated by a motor, and a wiper that is in close contact with a part of the housing glass is provided. A means for removing water droplets and dirt adhering to the housing glass is disclosed.

JP 2001-171491 A JP 2006-86640 A

However, in the conventional configuration, it is necessary to install a compressed air generating unit, a motor for rotating the casing glass, and a wiper along with the camera (imaging device). For this reason, there is a problem in that a large space is required around the camera, and the number of components increases, which is expensive.
In particular, when mounted on a vehicle, the mounting space on the vehicle side is often limited, and thus it is necessary to install the imaging device as compactly as possible.
An object of the present invention is to provide an image pickup apparatus that easily removes water droplets attached to the surface of a lens and prevents dirt from adhering to the lens, and a method for removing water droplets from the lens, while saving space. To do.

To achieve the above object, the present invention includes an imaging apparatus main body whose optical axes Ru are arranged vertically downward, and a lens exposed to the outside air are disposed on the front side of the image pickup apparatus main body, said lens A hydrophilic coating and a water-repellent coating are applied to the surface of the lens, and these coating areas are divided by two boundary lines having a substantially V shape, and the boundary lines are in contact with each other in the vicinity of the lowest point of the lens . It is characterized by.

  In this configuration, the hydrophilic coating may be applied to a region of the lens through which the optical axis passes. Further, when the lens intersects a perpendicular extending vertically downward from the center of the radius of curvature of the lens, the intersecting position may be the lowest point.

In addition, when a perpendicular extending vertically downward from the center of the radius of curvature of the lens and the lens do not intersect, the lens edge closest to the perpendicular may be the lowest point. Further, the surface of the lens, said each extending radially from the center point hydrophilic coated area and the water-repellent coated area of the lens to be the lowest point may be provided.

The present invention is disposed on the front side of the image pickup apparatus main body in which the optical axis is Ru are arranged vertically downward, a water drop removal method for removing water droplets adhering to the surface of the lens exposed to the outside air,
Applying a hydrophilic coating and water repellent coating on the surface of the lens, these coating region is divided by two boundary lines having a substantially V-shaped, the boundary line is in contact with the lowest point near the lens And water droplets adhering to the area where the hydrophilic coating is applied are guided to the lowest point along the boundary line.

According to the present invention, an imaging apparatus main body whose optical axes Ru are arranged vertically downward, and a lens exposed to the outside air are disposed on the front side of the image pickup apparatus main body, the hydrophilic coating and the surface of the lens A water-repellent coating is applied, and these coating regions are divided by two boundary lines having a substantially V-shape, and the boundary lines are in contact with each other in the vicinity of the lowest point of the lens. The water droplets adhering to the lens surface can be guided to the lowest point of the lens along the boundary line, and the adhering water droplets can be efficiently removed. Further, since only a hydrophilic coating and a water-repellent coating are applied to the surface of the lens and no device such as a compressed air generation unit is installed, space saving and cost reduction can be realized.

BRIEF DESCRIPTION OF THE DRAWINGS It is the figure which showed typically the imaging device which concerns on 1st Embodiment of this invention, (A) is the side view seen from the side in the attachment state, (B) looks at (A) from the front direction. FIG. It is a figure which shows the hydrophilic coating and water-repellent coating which were given to the lens of the imaging device. It is a figure explaining the flow of the water droplet adhering to a lens. It is a figure which shows the modification of the lens to which the hydrophilic coating and the water repellent coating were given. It is a figure which shows another modification of the lens to which the hydrophilic coating and the water repellent coating were given. It is the figure which showed typically the imaging device which concerns on 2nd Embodiment, (A) is the side view seen from the side in the attachment state, (B) is the front view which looked at (A) from the front direction It is. It is a figure which shows the area | region of the hydrophilic coating and water-repellent coating which were given to the surface of the lens of an imaging device. It is the side view which looked at the imaging device concerning a 3rd embodiment from the side in the attachment state. It is a figure which shows the area | region of the hydrophilic coating and water-repellent coating which were given to the surface of the lens of an imaging device.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
<First Embodiment>
FIG. 1 is a diagram schematically illustrating an imaging apparatus according to a first embodiment of the present invention, in which (A) is a side view as viewed from the side in an attached state, and (B) illustrates (A). It is the front view seen from the front direction.
The imaging device 10 includes a camera device body (imaging device body) 11 and a lens 13 provided on the front surface of the camera device body 11. This lens 13 is a convex lens having a spherical shape with a wide radius of curvature and a radius of curvature r, and is attached to the camera apparatus body 11 while ensuring water tightness.

  The imaging device 10 is a device that is used in a state where the lens 13 is exposed to the outside air. For example, the imaging device 10 is a vehicle camera device that is used outdoors such as a vehicle rear vision camera or a vehicle side view camera. As shown in FIG. 1, the camera apparatus body 11 has an optical axis P below the horizontal direction so as to be able to photograph objects on the road surface (display of road lanes, vehicles, pedestrians, obstacles, etc.). It is installed behind or on the side of the vehicle body (not shown).

A system equipped with a vehicle-mounted camera device in recent years is equipped with a function of recognizing road lanes and obstacles by an image recognition technique using an image taken by the camera device body 11. In this type of in-vehicle camera device, raindrops and dirt are likely to adhere to the surface of the lens 13 due to the weather and the surrounding environment, and the captured image may become unclear. It is assumed that it cannot be recognized correctly.
In this configuration, in order to easily remove water droplets adhering to the surface of the lens 13 and to prevent dirt from adhering to the lens 13, a combination of a hydrophilic coating and a water repellent coating is applied to the surface of the lens 13. ing.

Next, the coating on the surface of the lens 13 will be described.
As shown in FIG. 1A, the lens 13 is a convex lens having a spherical shape with a radius of curvature r, and the imaging apparatus 10 provided with the lens 13 has an optical axis P that is a predetermined angle below the horizontal direction. It is attached so as to be inclined by θ.
In the present embodiment, on the lens 13, the center point A of the lens 13 through which the optical axis P passes, and the intersection H between the lens 13 and the perpendicular H extending vertically downward from the center O of the radius of curvature r of the lens 13 Is formed. This intersection Q is the lowest point of the lens 13 when the imaging device 10 is attached.

FIG. 2 is a diagram illustrating regions of the hydrophilic coating and the water-repellent coating applied to the surface of the lens 13 of the imaging device 10.
As shown in FIG. 2, the surface of the lens 13 is provided with a hydrophilic coating in one region 20 including the center point A of the lens 13, and a water repellent coating is applied to the other region 21 other than the one region 20. Has been. As a component of the hydrophilic coating, coating is performed by a method such as vacuum deposition using alkoxysilane, polyethylene glycol, photocatalyst (TiO ₂ ), organosiloxane, or the like. In addition, as a component of the water repellent coating, a silicon resin, a fluororesin, or the like is used for coating by a method such as vacuum vapor deposition as in the case of the hydrophilic coating.
In the case of coating, a hydrophilic coating is applied to the entire surface of the lens 13, and after masking one area 20, a water-repellent coating may be applied to the other area 21.

  In the present embodiment, one region 20 to which a hydrophilic coating is applied and another region 21 to which a water-repellent coating is applied are divided by two boundary lines 22 and 23 having a substantially V shape. . One end of each of the boundary lines 22 and 23 extends to the peripheral edge portions 13A and 13B in the horizontal direction of the lens 13 across the center point A of the lens 13, and the other end of the boundary lines 22 and 23 is an intersection of the lens 13 described above. It is in the vicinity of Q. As a result, the width of the one region 20 to which the hydrophilic coating is applied becomes smaller as it approaches the intersection Q.

When water droplets adhere to the lens 13 to which each of such coatings has been applied, the water droplets tend to become large lumps in one region 20 to which the hydrophilic coating has been applied, and the water droplets that have become large lumps flow by their own weight.
Specifically, as shown in FIG. 3, water droplets adhering to the surface of one region 20 of the lens 13 flow downward along the surface of the lens 13 due to their own weight, but other water-repellent coating is applied. When it flows down to the boundary lines 22 and 23 with the region 21, it flows down toward the intersection Q along the boundary lines 22 and 23. In this configuration, the boundary lines 22 and 23 are substantially V-shaped, and the width in the horizontal direction decreases as the intersection Q is approached, so that water droplets can be concentrated and guided to the intersection Q. Furthermore, since the intersection Q is the lowest point of the lens 13, the water droplets guided to the intersection Q are discharged downward as they are. Thereby, water droplets adhering to the surface of the lens 13 can be efficiently removed.

  In this configuration, since the hydrophilic coating is applied to the center point A of the lens 13 through which the optical axis P of the camera apparatus body 11 passes, a clear image can be taken through the lens 13 from which water droplets have been removed. . Further, since water droplets can be removed simply by applying a hydrophilic coating and a water repellent coating to the surface of the lens 13, it is not necessary to install a device such as a compressed air generating unit. Therefore, it is possible to realize the removal of water droplets adhering to the surface of the lens 13 in the in-vehicle camera device mounted on the vehicle with a small space and a low cost.

In the other region 21 to which the water repellent coating is applied, water droplets are repelled to form polka dots. This polka dot is wiped off by running of the vehicle. Further, when the imaging device 10 is an in-vehicle camera device, it is desirable that the other region 21 is attached so as to coincide with a region where a vehicle bumper or body is photographed.
This is because the captured image other than the region where the vehicle bumper or body is captured is an image processing region used for lane recognition or moving object recognition by image processing. That is, by matching the other area 21 in which water droplets (polka dots) may remain with the area where the bumper body of the vehicle is photographed, it does not interfere with the image processing by the photographed image of the in-vehicle camera device. be able to.

Further, the hydrophilic coating and the water-repellent coating applied to the surface of the lens 13 are not limited to the above-described forms, and other forms are also possible.
FIG. 4 is a view showing a modification of the lens 13 to which a hydrophilic coating and a water repellent coating are applied. The lens 13 is different from the above-described embodiment in the boundary lines 24 and 25 that divide one region 20 having a hydrophilic coating and another region 21 having a water repellent coating. Since other configurations are the same, the same reference numerals are given and description thereof is omitted.
In this modification, the boundary lines 24 and 25 are not straight lines but include bent portions 24A and 25A that are bent in the middle. Since the bent portions 24A and 25A are formed so as to protrude into the one region 20, the shape of the one region 20 can be freely changed, and the flowing water droplets stagnate in the middle of the boundary lines 24 and 25. Can be prevented.

FIG. 5 is a diagram showing another modification of the lens 13 to which a hydrophilic coating and a water repellent coating are applied. This modification is different in that it includes a plurality (two each) of one region 20A, 20B having a hydrophilic coating and another region 21A, 21B having a water repellent coating. About the same structure as above-mentioned embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.
In this modification, the hydrophilic coating and the water repellent coating are set to overlap in the height direction. The boundary lines 31 and 32, the boundary lines 33 and 34, and the boundary lines 35 and 36 that divide each region are formed in a substantially V shape, and the V-shaped corners of the boundary lines 31 and 32 arranged at the lowermost positions are The V-shaped corners of the other boundary lines 33 and 34 and the boundary lines 35 and 36 are arranged on straight lines connecting the center point A and the intersection Q, respectively.
According to this, the water droplets flowing along the boundary lines 31 and 32, the boundary lines 33 and 34, and the boundary lines 35 and 36 are guided to the respective V-shaped corners, and finally to the intersection Q. And discharged from intersection Q. Thereby, the water droplet adhering to the lens 13 can be removed efficiently.
In general, a vehicle-mounted camera is a relatively small camera, but the size of the camera device main body and the lens varies widely. In the case of a vehicle-mounted camera having a large lens, since the area of the lens becomes large, there is a concern about the stagnation of water droplets on the lens surface.
However, by forming the hydrophilic coating and the water-repellent coating in a substantially V shape as in this configuration, it is possible to suppress the stagnation of water droplets adhering to the surface and efficiently remove the water droplets. This configuration is effective when used for a relatively large lens.
In this configuration, a water repellent coating is applied to a portion near the center of the lens 13. However, if the other area 21A to which the water-repellent coating is applied is an area that does not interfere with the visual field to be secured and the image recognition processing area, the in-vehicle camera does not have a functional problem. Therefore, the hydrophilic and water-repellent coating regions may be determined in consideration of the field of view and the image recognition processing region.

Second Embodiment
6A and 6B are diagrams schematically illustrating an imaging device 50 according to the second embodiment of the present invention. FIG. 6A is a side view of the imaging device 50 viewed from the side in an attached state, and FIG. It is the front view which looked at from the front direction.
The camera device main body 11 of the imaging device 50 according to the second embodiment is the same as the imaging device 10 described above in that the optical axis P is installed downward from the horizontal direction. And the horizontal direction are different from each other at a predetermined angle θ.
Specifically, in the above-described embodiment, the perpendicular H extending vertically downward from the center O of the radius of curvature r of the lens 13 intersects the lens 13 at the intersection Q. However, when the predetermined angle at which the imaging device 50 is inclined is reduced, the perpendicular H and the lens 13 do not intersect as shown in FIG.
Therefore, in this configuration, the lower end edge Q1 of the lens 13 having the shortest distance L from the perpendicular H is the lowest point, and the region is divided so that the boundary line substantially coincides with the lower end edge Q1.

FIG. 7 is a diagram illustrating regions of the hydrophilic coating and the water-repellent coating applied to the surface of the lens 13 of the imaging device 50.
As shown in FIG. 6, the surface of the lens 13 is provided with a hydrophilic coating in one region 60 including the center point A of the lens 13, and a water repellent coating is applied in the other region 61 other than the one region 60. Has been. In the present embodiment, one region 60 to which the hydrophilic coating is applied and the other region 61 to which the water-repellent coating is applied are divided by two boundary lines 62 and 63 having a substantially V shape. . One end of each boundary line 62, 63 extends to the peripheral edge portions 13A, 13B of the lens 13 across the center point A of the lens 13, and the other end of the boundary lines 62, 63 is the lower end of the lens 13. It coincides in the vicinity of the edge Q1.
In this configuration, even when the predetermined angle at which the imaging device 50 is attached is small, the boundary lines 62 and 63 for partitioning the coating are matched in the vicinity of the lower end edge Q1 of the lens 13, so The end portions of the boundary lines 62 and 63 can be aligned with the positions. Thereby, the width of the mounting angle of the imaging device 50 can be given, and the mounting operation of the imaging device 50 can be easily performed.

<Third Embodiment>
FIG. 8 is a side view of the imaging device 70 according to the third embodiment of the present invention as viewed from the side in an attached state, and FIG. 9 shows a hydrophilic coating applied to the surface of the lens 13 of the imaging device 70 and repellent properties. It is a figure which shows the area | region of a water coating.
This third embodiment differs from the above-described embodiment in that the optical axis P of the camera device body 11 of the imaging device 70 is installed vertically downward.
In this embodiment, the optical axis P of the camera apparatus body 11 and the perpendicular H extending vertically downward from the center O of the radius of curvature r of the lens 13 coincide with each other, and these pass through the center point A of the lens 13. For this reason, the center point A functions as the lowest point of the lens 13, and the region is divided so that the boundary line substantially coincides with the center point A.

On the surface of the lens 13, as shown in FIG. 9, one region 80A, 80B extending radially from the center point A of the lens 13 toward the periphery, and another region 81A, other than the one region 80A, 80B, 81B is formed. One region 80A, 80B is provided with a hydrophilic coating, and the other region 81A, 81B is provided with a water repellent coating.
These regions 80A, 80B, 81A, 81B are divided into substantially the same size by four boundary lines 82, 83, 84, 85 each having a substantially V shape. One end of each boundary line 82 to 85 extends to the peripheral edge of the lens 13, and the other end of the boundary line 82 to 85 coincides in the vicinity of the center point A that is the lowest end of the lens 13.
The regions 80A and 80B to which the hydrophilic coating is applied and the regions 81A and 81B to which the water repellent coating is applied are alternately formed in the circumferential direction of the lens 13.

According to this configuration, the water droplets flowing along the respective boundary lines 82 to 85 are guided to the central point A that is the corner of each V-shape and discharged from the central point A. Thereby, the water droplet adhering to the lens 13 can be removed efficiently.
In this configuration, since the hydrophilic coating and the water repellent coating are alternately arranged in the circumferential direction, the lens 13 is provided with a water repellent coating in a substantially half region. Even in this case, if the coating direction is determined in such a direction that a field of view and a processing area for image recognition can be ensured, the in-vehicle camera does not cause a functional problem.
For example, although the front of the vehicle is a portion that enters the driver's field of view, the rear of the vehicle does not enter the driver's field of view, and the vehicle-mounted camera is a region where the field of view and image recognition are desired. For this reason, what is necessary is just to design so that a hydrophilic coating may face the field of vision and the image recognition area with this vehicle-mounted camera.
If each coating is finely and alternately applied to the surface of the lens 13 in the circumferential direction, the effect of removing water droplets on the surface of the lens 13 is enhanced, so that the area of the water repellent coating region can be reduced.
In this embodiment, the surface of the lens 13 is divided into four regions, but it goes without saying that the number of these regions may be increased or decreased. In this embodiment, each of the regions 80A, 80B, 81A, 81B is divided into substantially the same size. However, the present invention is not limited to this, and the size of the regions 81A, 81B on which the water repellent coating is applied. May be made smaller than the regions 80A and 80B where the hydrophilic coating is applied, and the removal of water droplets on the surface of the lens 13 is positively promoted to ensure the field of view of the lens 13.

10, 50, 70 Imaging device 11 Camera device body (imaging device body)
13 Lens 20, 20A, 20B, 60, 80A, 80B One area 21, 21A, 21B, 61, 81A, 81B Other area 22, 23, 24, 25, 31, 32, 33, 34, 35, 36, 62, 63, 82, 83, 84, 85 Boundary line 24A, 25A Bending part A Center point (lowest point)
H perpendicular L distance O center P optical axis Q intersection (bottom point)
Q1 Bottom edge (lowest point)
r Curvature radius

Claims (6)

An imaging apparatus main body whose optical axes Ru are arranged vertically downward, and a lens exposed to the outside air are disposed on the front side of the image pickup apparatus main body, subjected to a hydrophilic coating and water repellent coating on the surface of the lens, These coating regions are divided by two boundary lines having a substantially V shape, and the boundary lines are in contact with each other in the vicinity of the lowest point of the lens.   The imaging device according to claim 1, wherein the hydrophilic coating is applied to a region of the lens through which the optical axis passes.   3. The imaging device according to claim 1, wherein when the lens intersects a perpendicular extending vertically downward from the center of the radius of curvature of the lens, the intersecting position is the lowest point. 4. .   The edge of the lens closest to the perpendicular is the lowest point when the normal does not intersect with the perpendicular extending vertically downward from the center of the radius of curvature of the lens. 2. The imaging device according to 2. On the surface of the lens, to claim 1, characterized in that said each extending radially from the center point hydrophilic coated area and the water-repellent coated area of the lens to be the lowest point is provided The imaging device described. Disposed on the front side of the image pickup apparatus main body in which the optical axis is Ru are arranged vertically downward, a water drop removal method for removing water droplets adhering to the surface of the lens exposed to the outside air,
Applying a hydrophilic coating and water repellent coating on the surface of the lens, these coating region is divided by two boundary lines having a substantially V-shaped, the boundary line is in contact with the lowest point near the lens A method for removing water droplets, characterized in that water droplets adhering to a region coated with a hydrophilic coating are guided to the lowest point along the boundary line.

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