JP6924130B2 - Lens and imaging device - Google Patents

Description

The present invention relates to a lens and an imaging device.

Conventionally, in a system in which an in-vehicle camera is installed outside a vehicle, various stains may adhere to the lens surface of the in-vehicle camera due to weather, mud, dust, and the like. Dirt adhering to the lens surface causes deterioration of optical characteristics due to water droplets adhering to the lens surface, such as flare, white spots, white turbidity, vignetting, out-of-focus, and abnormal distortion, and various countermeasures have been proposed. There is.

For example, a deposit wiping device has been proposed in which a magnetic material and a permanent magnet are driven by adjusting the magnetic force of a coil, and water droplets adhering to the lens are wiped off by a wiper arm (for example, Patent Document 1). However, in this deposit wiping device, there is a concern that the wiper arm stretches the dirt contained in the water droplet itself or causes the dirt to be left unwiped.

On the other hand, a water droplet removing method has also been proposed in which water droplets adhering to the lens surface are removed by applying a hydrophilic coating and a water repellent coating to the lens surface without using a mechanical element such as a wiper arm. (For example, Patent Document 2).

Japanese Unexamined Patent Publication No. 2014-125104 JP 2015-18106

In the water droplet removing method disclosed in Patent Document 2, the direction in which the lens is incorporated into the camera device main body is uniquely determined. That is, when it is incorporated in the camera device main body, it is fixed only in a unique positional relationship. That is, the posture of the lens capable of exhibiting the desired optical characteristics is limited to only one. Therefore, it is physically impossible to install the lens upside down or upside down. As a result, strict visual positioning is required when incorporating the lens into the camera device body.

The present invention has been made in view of the above problems, and suppresses deterioration of optical characteristics due to water droplets adhering to the lens surface while avoiding the trouble of visually positioning the lens when it is attached to the camera device main body. It is an object of the present invention to provide a lens and an imaging device capable of performing the same.

The lens according to the present invention is a lens arranged on an optical path in which water droplets are interposed, and has a water-repellent coat and a hydrophilic coat formed on a lens surface intersecting the optical path. A plurality of linear regions extending from the peripheral edge portion of the lens surface and the peripheral portion toward the outside of the central portion of the lens surface are formed, and the hydrophilic coat is formed on the region between the plurality of linear regions and the lens surface. It is characterized in that it is formed in the central portion of the lens.

The image pickup apparatus according to the present invention includes a lens according to the present invention, an image pickup element having an image pickup surface that receives an image through the lens surface, and a housing to which the lens and the image pickup element are attached. It is characterized by.

According to the lens and the image pickup apparatus according to the present invention configured in this way, the optical characteristics caused by the water droplets adhering to the lens surface are avoided while avoiding the trouble of visually positioning the lens when it is attached to the camera apparatus main body. Deterioration can be suppressed.

It is a perspective view which shows typically the image pickup apparatus which concerns on one Embodiment of this invention. It is explanatory drawing which shows the hydrophilic coating and water-repellent coating formed on the lens surface. It is a figure explaining the flow of water droplets adhering to a lens (the 1). It is a figure explaining the flow of water droplets adhering to a lens (the 2). It is a figure explaining the lens which concerns on the modification (the 1). It is a figure explaining the lens which concerns on the modification (the 2).

Hereinafter, specific embodiments of the lens and the image pickup apparatus according to the present invention will be described with reference to the drawings.

(Explanation of imaging device)
FIG. 1 is a perspective view schematically showing an image pickup apparatus in which a lens according to an embodiment of the present invention is incorporated in an optical system.

The image pickup device 10 is an in-vehicle camera device used outdoors such as an in-vehicle rear vision camera and an in-vehicle side view camera. A system equipped with an in-vehicle camera device is equipped with a function of recognizing a lane or an obstacle on a road by an image recognition technology using an image captured by the image pickup device 10.

The image pickup apparatus 10 is attached, for example, in the front portion of a vehicle (not shown) so that the optical axis P passing through the center of the lens 12 faces downward from the horizontal direction. As a result, the image pickup device 10 captures an image of an object on the road surface, such as a display of a lane of a road in front of the vehicle, a vehicle, a pedestrian, an obstacle, or the like.

The image pickup device 10 includes a camera device main body 11 (housing) and a lens 12 attached to the front surface of the camera device main body 11.

(Lens configuration)
Hereinafter, the configuration of the lens 12 will be described.

The lens 12 is, for example, a convex lens arranged on an optical path in which a water droplet DW (FIG. 3) is interposed, and as shown in FIG. 2, the lens surface 13 intersecting the optical path has a spherical shape.

The lens 12 is devised to efficiently remove water droplets DW adhering to the lens surface 13. That is, the lens 12 has a water-repellent coating 12r and a hydrophilic coating 12h formed on the lens surface 13.

The water-repellent coat 12r is formed on the peripheral edge portion 13r of the lens surface 13 and the linear regions 14a, 14b, 14c, 14d, 14e, 14f, 14g, and 14h. In the following, when the linear regions 14a to 14h are not particularly distinguished, they are also simply referred to as the linear regions 14. The thickness of the water-repellent coat 12r formed on the peripheral edge portion 13r is, for example, 0.9 mm. The thickness of the water-repellent coat 12r formed on the peripheral edge portion 13r is preferably 0.5 mm to 2.0 mm. As a component of the water-repellent coat 12r, for example, a silicon resin, a fluororesin, or the like is used.

The hydrophilic coat 12h comprises the regions 15a, 15b, 15c, 15d, 15e, 15f, 15g, 15h between the linear regions 14a, 14b, 14c, 14d, 14e, 14f, 14g, 14h and the central portion 13c of the lens surface 13. Is formed in. In the following, when the regions 15a to 15h are not particularly distinguished, they are also simply referred to as regions 15. As a component of the hydrophilic coat 12h, for example, alkoxysilane, polyethylene recall, photocatalyst (TiO ₂ ), organosiloxane, or the like is used.

The linear regions 14a to 14h are regions extending from the peripheral edge portion 13r toward the outside of the central portion 13c of the lens surface 13. The linear regions 14a to 14h are arranged at equal angles about the central portion 13c of the lens surface 13 and are arranged at equal intervals in the circumferential direction of the lens surface 13.

(Lens manufacturing method)
Next, a method of manufacturing a lens will be described. As an example of the manufacturing method, a step of forming the hydrophilic coat 12h on the entire surface of the lens surface 13 and a step of forming the water-repellent coating 12r on the peripheral edge portion 13r and the linear regions 14a to 14h may be performed in this order. As a coating method, vacuum vapor deposition may be used, or coating may be performed by a sol-gel method, spin coating, inkjet, or the like.

According to the lens and the image pickup apparatus according to the embodiment configured as described above, since the number of linear regions 14a to 14h is an even number (8), the linear regions 14a and 14e are aligned with each other, and the linear regions 14b, The 14fs, the linear regions 14c and 14g, and the linear regions 14d and 14h can be assigned to point-symmetrical positions. As a result, the directionality in which the lens 12 is attached to the camera device main body 11 can be further eliminated. Therefore, it is physically possible to incorporate the lens 12 horizontally upside down or upside down with respect to the camera device main body 11. As a result, it is possible to eliminate strict visual positioning when the lens 12 is incorporated into the camera device main body 11.

Further, the water-repellent coat 12r is formed in the linear regions 14a to 14h in addition to the peripheral edge portion 13r of the lens surface 13. That is, the water-repellent coat 12r is formed only on a part of the lens surface 13, not on the entire surface. That is, since the region where the water-repellent coat 12r is formed is small, the phenomenon that the adhesion state between the lens surface 13 and the water droplet DW is maintained due to the adsorption force of the water droplet DW itself is unlikely to occur. In addition, even if a small amount of water droplet DW remains on the water-repellent coat 12r, the deterioration of the optical characteristics due to the water droplet DW does not proceed more than necessary.

Further, a hydrophilic coat 12h is applied to the central portion 13c through which the optical axis passes. That is, the water-repellent coat 12r is not applied to the central portion 13c. Therefore, the image near the center, which plays an important role as a camera image, is not adversely affected by the water droplet DW. Specifically, it is possible to prevent or suppress the water droplet DW formed in the central portion 13c from causing light scattering. Therefore, it is possible to prevent or suppress the image near the center formed through the central portion 13c from becoming unclear. As a result, the image pickup apparatus 10 can capture an image having a clear center vicinity through the lens 12.

Further, since the water-repellent coat 12r is formed in the linear regions 14a to 14h adjacent to the regions 15a to 15h in which the hydrophilic coat 12h is formed, the water film WF adhering to the hydrophilic coat 12h is removed from the water-repellent coat 12r. It can be quickly changed to a granular shape by the surface tension of (Fig. 3). The water droplet DW that has changed into a granular shape from the water film WF rolls down toward the lower side of the lens surface 13 due to the weight of the water droplet DW or the vibration of the vehicle (FIG. 3).

The water droplet DW that has rolled off is biased toward the hydrophilic coat 12h under the lens surface 13, so that it may become a water film WF (FIG. 4) again and adhere to the lens surface 13. Also in this case, the water film WF (FIG. 4) can be dropped toward the lower side of the lens surface 13 by its own weight or the vibration of the vehicle. This is because the water film WF changes into a granular shape as soon as the water film WF (FIG. 4) touches the water repellent coat 12r formed on the peripheral edge portion 13r of the lens surface 13.

The water droplet DW, which has been changed into a granular shape from the water film WF (FIG. 4), has less contact with the lens surface 13. As a result, the frictional force between the water droplet DW and the lens surface 13 is reduced. Therefore, the granular water droplet DW can be rolled down to the lower side of the lens surface 13 by utilizing the uneven uneven portion or the inclined portion of the lens surface 13.

That is, the water droplet DW adhering to the hydrophilic coat 12h as a water film WF is delivered to the water-repellent coat 12r, so that the surface tension of the water-repellent coat 12r quickly changes its appearance into particles and moves to the outside of the lens 12. It will be excluded. The elimination of such water droplets DW is further promoted by the cooperation of the hydrophilic coat 12h and the water repellent coat 12r. As a result, the water droplet DW can be efficiently removed to the outside of the lens 12 to the extent that deterioration of the optical characteristics due to the water droplet DW can be suppressed.

Further, since the water droplet DW can be removed only by forming the water-repellent coating 12r and the hydrophilic coating 12h on the lens surface 13, it is not necessary to separately install a device dedicated to removing water droplets such as a compressed air generation unit. Therefore, the removal of water droplets DW adhering to the surface of the lens 12 in the image pickup apparatus 10 mounted on the vehicle can be realized at low space and low cost.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the present invention is not limited to the configuration of the embodiments because the embodiments are merely examples of the present invention. It goes without saying that even if there is a design change or the like within a range that does not deviate from the gist, it is included in the present invention.

In the above embodiment, an example of applying the present invention to a convex lens is shown. However, it is not limited to this. For example, the present invention may be applied to a lens such as a concave lens or an aspherical lens.

In the above embodiment, an example in which the number of linear regions 14 is eight is shown. However, it is not limited to this. For example, the number of linear regions 14 may be 16 (FIG. 5). Also in this modification, as shown in FIG. 5, linear regions 14a, 14i, linear regions 14b, 14j, linear regions 14c, 14k, linear regions 14d, 14l, linear regions 14e, 14m, linear regions 14f, 14n, linear regions 14g, 14o, and linear regions 14h, 14p can be assigned to point-symmetrical positions.

In short, as shown in FIG. 5, the number of the linear regions 14 may be an even number that can allocate the linear regions 14 to the point-symmetrical positions. In the modified example shown in FIG. 5, since the number of linear regions 14 can be doubled from 8 to 16, the surface tension of the water-repellent coat 12r formed in the linear regions 14 causes the water film WF to become granular. The amount of water droplet DW that changes its appearance can also be doubled or more. As a result, the elimination of water droplets DW adhering to the lens surface 13 can be further promoted.

In the above embodiment, an example is shown in which the thickness of the water-repellent coat 12r formed on the peripheral edge portion 13r is 0.9 mm. However, it is not limited to this. For example, the thickness of the water-repellent coat 12r may be 2.0 mm, which is larger than 0.9 mm (FIG. 6). In this modification, the area of contact with the water film WF can be increased by the amount that the thickness of the water-repellent coat 12r formed on the peripheral edge portion 13r is increased. Therefore, it is possible to increase the amount of water droplet DW that changes its appearance from the water film WF into particles by the surface tension of the water repellent coat 12r. As a result, the elimination of water droplets DW adhering to the lens surface 13 can be further promoted.

In the above embodiment, an example is shown in which an image pickup device 10 in which a lens 12 having the above characteristics is incorporated in an optical system is applied to an in-vehicle camera device. However, it is not limited to this. For example, the image pickup device 10 may be applied not only to an in-vehicle camera device but also to a surveillance camera, a security camera, or the like that are often installed outdoors where the temperature changes greatly.

10 ... Imaging device 11 ... Camera device body (housing)
12 ... Lens 12h ... Hydrophilic coating 12r ... Water repellent coating 13 ... Lens surface 13c ... Central 13r ... Peripheral portions 14, 14a, 14b, 14c, 14d, 14e, 14f, 14g, 14h ... Linear region 15, 15a, 15b, 15c, 15d, 15e, 15f, 15g, 15h ... Region DW ... Water droplet WF ... Water film

Claims (5)

A lens placed on an optical path with water droplets.
It has a water-repellent coat and a hydrophilic coat formed on the lens surface that intersects the optical path.
The water-repellent coating is formed on a peripheral edge portion of the lens surface and a plurality of linear regions extending from the peripheral edge portion toward the outside of the central portion of the lens surface.
A lens characterized in that the hydrophilic coat is formed in a region between the plurality of linear regions and in the central portion of the lens surface. In the lens according to claim 1,
The lens is characterized in that the linear region is formed on the lens surface at equal angular intervals about the central portion of the lens surface. In the lens according to claim 1 or 2.
A lens characterized in that the number of linear regions is an even number. In the lens according to any one of claims 1 to 3.
A lens characterized in that the thickness of the water-repellent coating formed on the peripheral edge portion is 0.5 mm to 2.0 mm. The lens according to any one of claims 1 to 4.
An image sensor having an image pickup surface that receives an image through the lens surface, and an image pickup device.
An image pickup apparatus comprising the lens and a housing to which the image pickup element is attached.

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