In-vehicle camera unit having camera built into body

An in-vehicle camera unit has a body to which a lens is attached and prevention members that prevent water drops from falling on the lens. Specifically the body has a top surface where the lens is arranged, a front surface of the lens being exposed to an outside of the body. The top surface has an oblique portion extending from the periphery of the lens backward of the lens. The oblique portion is oblique in such a way as to be away from the optical axis 13a of the lens with increasing distance from the lens backward. The prevention member is provided in or on the oblique portion across an oblique direction of the oblique portion.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims the benefit of priority from earlier Japanese Patent Application No. 2010-284773 filed on Dec. 21, 2010, the description of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

The present invention relates to an in-vehicle camera unit having a camera built into a body. In particular, the present invention is related to the structure of the body of the in-vehicle camera unit.

2. Related Art

Recent year, techniques for equipping an in-vehicle camera on board and using the images taken by the in-vehicle camera are put to practical use. There is a technique for assisting a user to drive a vehicle on the basis of images taken by in-vehicle camera as an example of such techniques (JP-U-1993-32191).

Sometimes the in-vehicle camera is attached to a windshield of the vehicle.

In a case where the windshield of the vehicle slopes forward and downward, the in-vehicle camera is positioned under the windshield. When dew condensation forms on the inside surface of the windshield, the dew drop may fall on the lens of the in-vehicle camera. Alternatively, the dew drop which has fallen on other areas may flow down other surfaces and reach the lens. In this case, the image-recognition capability may be reduced or lost.

SUMMARY

According to the present disclosure, an in-vehicle camera unit which can prevent water drops adhering to a lens is provided. According to one aspect of the present disclosure, an in-vehicle camera unit have a body to which a lens is attached, and a prevention member that prevents water drops from falling on the lens, wherein the body has a first surface where the lens is arranged, a front surface of the lens being exposed to an outside of the body, the first surface has an oblique portion extending from the periphery of the lens backward of the lens, the oblique portion being oblique in such a way as to be away from the optical axis of the lens with increasing distance from the lens backward, and the prevention member is provided in or on the oblique portion across an oblique direction of the oblique portion.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

1. The Configuration of the In-vehicle Camera Unit

A first embodiment will be described with reference toFIG. 1toFIG. 5A.FIG. 1is a perspective view of a main portion3of an in-vehicle camera unit1. The main portion3is described below.FIG. 2is a top view of the in-vehicle camera unit1.FIG. 3is a front view of the in-vehicle camera unit1.FIG. 4is a cross sectional side view taken from line IV-IV ofFIG. 2.FIG. 5Ais a cross-section view taken from line V-V which shows prevention members15,17and the periphery of them. The prevention members15,17are described below.

The in-vehicle camera unit1has a main portion3and bracket5. As shown inFIG. 1, the main portion3has a body7and compositions (not shown in figures) of camera CA which are publicly known. The compositions including lens13are accommodated in the body7. The in-vehicle camera unit1of this embodiment is attached to a car, with the lens13facing the windshield21of the car. The windshield21slopes forward and downward. The forward direction of the car is indicated by the arrow Y inFIG. 4. The body7has a top surface9(corresponding to a “first surface” in the claims) sloping along the windshield21. With respect to the lens13, the top surface9is oblique in such a way as to be away from the optical axis13aof the lens13with increasing distance from the lens13backward of the lens13. The front-back direction along the top surface9is described bellow as the oblique direction C. Thus, by forming the top surface9in the same shape as the windshield21, the in-vehicle camera unit1can be stably attached close to the windshield21.

The recess11is formed in the top surface9. The recess11continues to the front end of the top surface9. The side surfaces11b,11c,11dof the recess11are exposed to the front side. The inside bottom11aof the recess11has a lower pitch than the rest portion of the top surface9except the recess11. The lens13is attached to the lens attached surface11bwhich is the side surface facing forward, so lens13is exposed and facing forward. The recess11is a space to assure angle of view of the camera.

Two prevention members15,17are provided at the top surface9. The prevention members15,17surround three directions of the recess11except the front direction. That is, the prevention members15,17extend across the oblique direction C on an oblique portion9awhich is a portion of the top surface and positioned backward from the recess11(in other words, the oblique portion is the portion which has a rising pitch along the oblique direction C from the lens13). Further, in this embodiment, the prevention members15,17extend along the periphery of the recess11from there to the front end of the top surface9. In this way the prevention members15,17guide water drops fallen from the windshield21to a position where the guided water drops do not hinder the field angle of the camera.

Portions on the oblique portion9aof the prevention members15,17are made in a nearly V-shape opening to the lens13as viewed from the front of the top surface9. The bend portion15a,17aof this V-shaped portion (which is in the middle of the prevention members15,17and facing backward of the oblique direction) is treated with round chamfering, and rounded.

FIG. 5Ais cross-section view taken from line V-V ofFIG. 2, which shows the prevention members15,17and the periphery of them. Each of the prevention members15,17is a dike (or a protrusion) formed on the top surface9, and each dike's top is one revel higher than the main of the top surface9. Thus, the prevention members15,17form a structure bearing two dikes provided along the oblique direction. The prevention members15,17have the same cross-section shape in any portion.

The edges of the prevention members15,17are rounded by round chamfering, as the edges are circled inFIG. 5A. The crooked portion in the top and base of the dike has curved surface. The prevention members15,17of this embodiment are provided at some interval19where there is not a dike, trench and so on, and which is a flat surface.

The main portion3of the in-vehicle camera unit1is attached to the windshield21by using a bracket5. The bracket5, inFIG. 2toFIG. 4, has a flat plate-like attachment portion5A and a pair of holding portions5B,5B. The plate-like holding portions5B,5B respectively hang down from both ends of the attachment portion5A. The bracket5, inFIG. 3, holds the main portion3such that the both side surface of the main portion3are respectively fixed to holding portions5B,5B. The bracket5is attached to the windshield21by bonding the top surface of the attachment portion5A.

In a state where the in-vehicle camera unit1is attached to the windshield21through the bracket5, the lens13of the in-vehicle camera unit1is directed forward of the vehicle, and the top surface9slopes forward and downward. In this state, as shown inFIG. 3, the attachment portion5A of the bracket5and the top surface of the main portion3face each other, keeping predetermined distance X between each other. The top surfaces9of the main portion3faces the windshield21, sandwiching the attachment portion5A between them. Keeping the predetermined distance X can prevent dew drops from flowing down the bracket5to the lens13.

A cutout portion5D of the bracket5, inFIG. 2, is formed by cutting out a portion of the attachment portion5A facing the recess11. This structure prevents the bracket5hindering the angle of view of the in-vehicle camera unit1. A portion of the attachment portion5A facing the prevention members15,17may be cut out. This structure can prevent dew drops which have adhered to the bracket5from falling on the lens13.

For example, the body7and the prevention member15,17may be made from metal materials by die-casting.

2. Effects of the In-vehicle Unit1According to this Embodiment

(1) The windshield21and the attachment portion5A of the bracket5face the top surface9of the in-vehicle camera unit1. The dew drops on the inside surface of the windshield21may fall on the top surface9directly or through the attachment portion5A. As dew drops fall on the oblique portion9awhich is a portion of the top surface9positioned backward from the lens13, the dew drops are inclines to flow down to the lens13because the top surface9slopes forward and downward.

In this case, the in-vehicle camera unit1can prevent the dew drop from adhering to the lens13by the prevention members15,17provided to surround the recess11where the lens13is attached.

(2) The prevention members15,17form a structure which bearing two dikes provided along the oblique direction. Thus the effect of the prevention of water drops is further increased.

Further these structures enable to prevent water drops from falling without making a projection of a dike or a step higher too much. The effect of the prevention of water drops is increased by making the top surface of the projection to slope.

(3) The prevention members15,17is made in nearly V-shape opening to the lens13. This structure can change the direction of the water drops that have flowed down the oblique portion9atoward left or right, so it prevents the water drops from adhering to the lens13.

(4) The prevention members15,17are provided at interval. Thus the effect of the prevention of water drops is further increased. This structure can extend lifetime of a mold or die as the body7is made by using the mold or die.

(5) Each of the edges of the prevention members15,17is treated with round chamfering to be rounded. The bend portion15a,17aare also treated with round chamfering, and rounded. These structure enable water drops to spread on the top surface9and change from a mass which easily fall into a state which hardly fall, so it prevent the water drops from falling on the lens13. Thus the effect of preventing water drops from adhering to the lens13is further increased.

(6) It is easy to attach the in-vehicle camera unit1having the bracket5to a vehicle.

3. A Test for Confirming the Effect of the In-vehicle Camera Unit1

InFIG. 3, water drops were chopped on 3 points P, Q, R in the main portion3, and the flows of the water drops were observed. As a result, in any cases it was confirmed that water drops had been prevented from reaching the recess by the prevention members15,17.

On the other hand, the same tests as described above were performed, using a main portion which basically had the same structure as the main portion3of this embodiment but didn't have prevention members15,17. As a result, it was observed that water chops had reached the recess and had adhered to the lens13.

Other embodiments will be described with reference toFIG. 5BtoFIG. 5D.

The present invention is not limited to the above-described embodiments. Modifications can be made accordingly without departing from the scope of the present invention.

For example, inFIG. 5B, trenches the bottoms of which are lower than the top face9may be made as prevention members15,17. InFIG. 5Cthe prevention member15may be the dike, and the prevention member17may be the trench. Alternatively, the prevention member17may be the dike, and the prevention member15may be the trench.

InFIG. 5Da step the top surface of which is higher than the top surface9may be made as a prevention member15.

The number of prevention members is not limited to2. For example, only a prevention member may be provided, and3,4,5or more prevention members may be provided.

The prevention members15,17may have right-angled edges without round chamfering.

As viewed from the front of the top surface9, the shapes of the prevention members15,17are not limited to V-shapes, but other shapes are allowed. For example, the prevention members15,17may be formed in a U-shape opening to the lens13, as viewed from the front of the top surface9.

The prevention members15,17are not limited to the structure which has the interval between each other, and a structure which has no interval may be allowed. For example, by piling the prevention member on top of another, the prevention members15,17may be formed in stair-like shapes.

The bracket5may be attached to an inside of a roof or to a place astride an inside of a roof and the windshield21. The in-vehicle camera unit1may be attached to a back window or the periphery of the back window, and take an image of backward of a vehicle. In that case, the direction of the in-vehicle camera unit is opposite to the one of the in-vehicle camera unit for taking an image of front of a vehicle. Alternatively, the in-vehicle camera unit1may be attached to a side window or the periphery of the side window, and take an image of side of a vehicle. In that case, the direction of the in-vehicle camera unit is set by rotating the direction of the in-vehicle camera unit for taking an image of front of a vehicle approximately 90 degree.

The prevention members15,17do not have to surround all three direction of the recess11. For example, they may be provided only in the area of the oblique portion9awhich can cover the width of the recess11(or the lens13).