JP6187765B2 - Lens attachment, camera, and driving support device - Google Patents

Description

  The present invention relates to a camera installed outdoors such as an in-vehicle camera or a surveillance camera.

  Cameras installed outdoors such as in-vehicle cameras and surveillance cameras are generally known. In the outdoors, raindrops or water vapor may cause water droplets to adhere to the lens surface. Water drops blur the captured image. An image sufficient for recognition cannot be obtained. It is desirable that water droplets be removed promptly.

Japanese Patent No. 4726698

  As disclosed in Patent Document 1, a drainage channel such as a groove is proposed for removing water droplets. The drainage channel is carved on the surface of the annular pressing member. The lens surface of the lens is exposed in the circular opening of the pressing member. The drainage channel extends outward from the edge of the circular opening. However, the water droplet does not easily move from the center of the lens surface to the edge of the lens surface by the weight of the water droplet or the vibration of the vehicle. A technique that promotes removal of water droplets is desired.

  According to some aspects of the present invention, an attachment for a lens that is attached to a camera and can contribute to the removal of water droplets more quickly than in the past can be provided.

  One embodiment of the present invention is attached to a camera having a lens surface, and a drainage channel for discharging water droplets attached to the lens surface is defined, and the position of the drainage channel is in the direction of gravity in the optical axis of the lens of the camera. Further, the present invention relates to an attachment for a lens, which is inside a circle centered on an optical axis defined by an edge of an opening exposing a lens surface of the lens.

  According to such a lens attachment, the entrance of the drainage channel can be closer to the center of the lens surface than in the prior art. Therefore, water droplets on the lens surface can enter the drainage channel at a position closer to the center of the lens surface than before. Thus, water droplets on the lens surface can be quickly removed from the lens surface. Such a lens attachment can be retrofitted to an existing in-vehicle camera or surveillance camera.

  The lens attachment includes a first piece extending along the lens surface from the edge of the opening to the inside of the circle below the optical axis in the direction of gravity, and below the optical axis in the direction of gravity. A second piece may be provided that extends along the lens surface from the edge to the inside of the circle and forms a slit between the first piece on the lens surface. Here, the drainage channel is formed by a slit. The entrance of the drainage channel is formed by the action of the slit. Thus, the entry of water droplets into the drainage channel is promoted.

  In the lens attachment, the width of the slit may increase as the distance from the optical axis increases in the direction of gravity. Capillary action causes water droplets on the lens surface to be taken into the slit drainage channel from the top entrance. Water flows down without staying in the drainage channel.

  The lens attachment as described above is attached to the camera. The camera can be equipped with a lens attachment. Such cameras and attachments can be used for driving support devices.

  As described above, according to the disclosed aspect, a lens attachment that is attached to a camera and can contribute to the removal of water droplets more quickly than in the past is provided.

It is a perspective view which shows roughly the structure of a motor vehicle provided with a driving assistance device. It is an expansion perspective view of a camera. It is an enlarged front view of a camera. It is a conceptual diagram which shows the relationship between an image circle and an imaging range. FIG. 5 is a horizontal sectional view taken along line 5-5 in FIG. It is an enlarged front view of the camera exposed to water splash. It is an enlarged front view of the camera which shows the mode of the water droplet which flows into a slit.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

(1) Configuration of Automobile and Driving Support Device FIG. 1 schematically shows an automobile 11 according to an embodiment. A driving support device 13 is mounted on the vehicle body 12 of the automobile 11. The driving support device 13 includes a navigation device 14. The navigation device 14 has a display panel 15. The display panel 15 can be incorporated in the dashboard of the automobile 11, for example. A map and other information can be displayed on the display screen of the display panel 15.

  The driving support device 13 includes a camera set 16. The camera set 16 is installed in the rear part of the vehicle body 12, for example. The camera set 16 is installed outdoors. The camera set 16 is attached above the rear bumper of the automobile 11, for example. The optical axis 17 of the camera set 16 is set at a predetermined angle with respect to the horizontal plane, for example. The optical axis 17 is inclined so as to approach the ground on which the automobile 11 is placed as it moves backward from the automobile 11. The camera set 16 images a subject behind the vehicle body 12. Here, a captured image of the subject is acquired in an angle of view range of at least ± 90 ° in both the horizontal and vertical directions with respect to the optical axis 17.

  The camera set 16 generates an image signal based on the captured image. In the image signal, a display image displayed on the display screen of the display panel 15 is specified. The camera set 16 is connected to the navigation device 14. An image signal is supplied from the camera set 16 to the navigation device 14. On the display screen of the display panel 15, an image behind the vehicle body 12 can be displayed based on the image signal. In the driving support device 13, for example, the driver can check the state behind the vehicle body 12 when entering the parking space in a parking lot by reverse running. In this way, the driving support device 13 can support the driver's backward confirmation.

(2) Structure of Camera As shown in FIG. 2, the camera set 16 includes a camera 21 and an attachment 22. An attachment 22 is attached to the camera 21. The attachment 22 is fixed to the camera 21. The attachment 22 covers the surface of the camera 21 with the lower half of the camera 21. The upper edge 22a of the attachment 22 crosses at least the front surface of the camera 21 in the horizontal direction.

  The camera 21 includes a housing 23. An opening 24 is defined in the housing 23 in front of the camera 21. The opening 24 has a circular contour. The outline of the opening 24 is modeled by the edge of the housing 23.

  A lens assembly 25 is accommodated in the housing 23. The lens assembly 25 defines a lens surface 26 at the forefront. The edge of the opening 24 has a circular shape and is in contact with the lens surface 26. The lens assembly 25 is formed of a plurality of lenses. The lens assembly 25 provides a fisheye lens or a wide angle lens.

  The attachment 22 defines a drainage channel 28. As is clear from FIG. 3, the drainage channel 28 is a circle centered on the optical axis 27 defined by the edge of the opening 24 below the virtual plane HP including the optical axis 27 and extending in the horizontal direction. It is arranged inside the circle 29 rather than 29. Here, the drainage channel 28 extends along the vertical plane VP including the optical axis 27.

  A first piece 31 and a second piece 32 are formed in the attachment 22 when the drainage channel 28 is partitioned. The first piece 31 extends while curving along the lens surface 26 from the edge of the opening 24 to the inside of the circle 29 below the virtual plane HP in the direction of gravity. Similarly, the second piece 32 extends along the lens surface 26 from the edge of the opening 24 to the inside of the circle 29 below the virtual plane HP in the direction of gravity. A slit 33 is formed between the first piece 31 and the second piece 32 in the direction of the vertical plane VP including the optical axis 27. The slit 33 forms a drainage channel 28 on the lens surface 26. The upper end 33a of the slit 33 is wide enough to cause capillary action. The width of the slit 33 gradually increases as the distance from the optical axis 27 increases.

  At least on the front surface of the camera 21, the upper edges of the first piece 31 and the second piece 32 (upper edge 22 a of the attachment 22) extend from the surface of the housing 23 outside the opening 24 onto the lens surface 26, and from the outside of the opening 24. It descends toward the slit 33. The inclination of the upper edge is continuous toward the slit 33 from both horizontal ends of the front surface.

  As shown in FIG. 4, in the camera set 16, the imaging range 36 of the imaging element is within the image circle 35 of the lens assembly 25. The imaging range 36 may be determined according to the shape (aspect ratio) of the display screen of the display panel 15, for example. At this time, the projection images 37 and 38 of the first piece 31 and the second piece 32 are located inside the image circle 35, but remain outside the imaging range 36. The image circle 35 corresponds to the edge (circle 29) of the opening 24. The imaging range 36 matches the contour of the imaging device.

  As shown in FIG. 5, the lens surface 26 and the upper edge of the first piece 31 may face each other with a fine interval. Thus, capillary action also occurs between the lens surface 26 and the upper edge of the first piece 31. Similarly, the lens surface 26 and the upper edge of the second piece 32 face each other at a fine interval. Capillary action occurs between the lens surface 26 and the upper edge of the second piece 32. The water droplets stored in the lens surface 26 and the first piece 31 and the second piece 32 by capillary action are finally sucked by the water droplets stored in the slit 33 and discharged from the drainage channel 28.

  When the automobile 11 travels in rainy weather or after rain, water splashes from the road surface. Or when it rains, water drops fall. As shown in FIG. 6, water splashes or water droplets adhere to the housing 23 of the camera 21 and the lens surface 26 of the lens assembly 25. As shown in FIG. 7, water droplets including those formed by aggregation of water droplets are collected in the slit 33. It flows downward from the slit 33. In this way, water droplets are removed from the lens surface 26.

  According to the attachment 22, the entrance of the drainage channel 28 can be closer to the center of the lens surface 26 than in the prior art. Therefore, water droplets on the lens surface 26 can enter the drainage channel 28 at a position closer to the center of the lens surface 26 than before. Thus, water droplets on the lens surface 26 can be quickly removed from the lens surface 26. Such an attachment 22 can be retrofitted to an existing in-vehicle camera or surveillance camera.

  In the camera set 16, the drainage channel 28 is formed by a slit 33. The entrance of the drainage channel 28 is formed on the lens surface 26 by the action of the slit 33.

  As described above, the upper end 33a of the slit 33 causes capillary action. Water droplets on the lens surface 26 are taken into the drainage channel 28 of the slit 33 from the entrance of the upper end 33a by the action of capillary action. The water flows down without staying in the drainage channel 28.

  In addition, capillary action occurs between the lens surface 26 and the edges of the first piece 31 and the second piece 32. When the water droplet becomes sufficiently large on the lens surface 26, the water droplet flows down toward the upper edges of the first piece 31 and the second piece 32 on the lens surface 26. Water droplets are guided toward the drainage channel 28 of the slit 33 along the upper edges of the first piece 31 and the second piece 32. Water droplets on the lens surface 26 are collected in the drainage channel 28 of the slit 33 by the effect of capillary action. In this way, the removal of water droplets is promoted.

  Note that the camera set 16 may be used not only for the driving support device 13 as described above but also for a surveillance camera. The attachment 22 may be retrofitted to the surveillance camera.

  13 driving support device, 16 camera, 21 camera body, 22 lens attachment, 22a upper edge, 24 aperture, 25 lens (lens assembly), 26 lens surface, 27 optical axis, 28 drainage channel, 29 yen, 31 first piece , 32 2nd piece, 33 slit, 33a upper end.

Claims (5)

A drainage channel that is attached to a camera having a lens surface and discharges water droplets attached to the lens surface is partitioned, and the drainage channel is positioned below the optical axis of the camera lens in the direction of gravity. An attachment for a lens that is inside a circle centered on an optical axis defined by an edge of an opening that exposes the lens surface of the lens, and is below the optical axis in the direction of gravity and from the edge of the opening to the inside of the circle A first piece extending along the lens surface, and extending along the lens surface from the edge of the opening to the inside of the circle below the optical axis in the direction of gravity, and the first piece on the lens surface And a second piece that forms a slit serving as the drainage channel, and the first piece and the second piece are in an image circle and form a projected image outside the image sensor. Lens attachment. 2. The lens attachment according to claim 1, wherein the first piece and the second piece are disposed outside a long side of the imaging element having an aspect ratio . 3. 3. The lens attachment according to claim 1 , wherein the width of the slit increases with increasing distance from the optical axis. 4. A camera comprising the lens attachment according to any one of claims 1 to 3 . A driving support device comprising the lens attachment according to any one of claims 1 to 4 .

Images