Abstract:
A driving assist device comprising: an imaging device that captures at least a portion of a vehicle-outside region configuring a blind spot for a driver; and a projection device that projects such that the driver views an image captured by the imaging device as a virtual image positioned at the vehicle outside of a vehicle component causing the blind spot.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a driving assist device. 
       BACKGROUND ART 
       [0002]    Technology is known that uses a display device provided at a front pillar to display an image of a region that is a blind spot for a driver caused by the front pillar (see, for example, Japanese Patent Application Laid-Open (JP-A) Nos. 2011-234095, 2012-051563 and 2008-307982). 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0003]    In technology such as the above, there is a concern regarding discomfort imparted to a driver due to a large perspective difference between the actual vehicle external scene and the image displayed on the display device. 
         [0004]    An object of the present invention is to obtain a driving assist device capable of suppressing discomfort when a driver views an image of a blind spot. 
       Solution to Problem 
       [0005]    A driving assist device according to a first exemplary embodiment of the present invention comprises: an imaging device that captures at least a portion of a vehicle-outside region configuring a blind spot for a driver; and a projection device that projects such that the driver views an image captured by the imaging device as a virtual image positioned at the vehicle outside of a vehicle component causing the blind spot. 
         [0006]    In this driving assist device, at least a portion of the vehicle-outside region configuring a blind spot for a driver is captured by the imaging device. Due to the projection device, the image captured by the imaging device is viewed by the driver as a virtual image positioned (or seeming to be) at the vehicle outside (far side) of the vehicle component configuring the blind spot. As a result, there is a smaller perspective difference (difference in viewing distance) between the actual vehicle external scene and the virtual image compared to a case in which an image (screen) of a display device disposed inside the vehicle is viewed, making a driver less liable to experience discomfort from the virtual image. 
         [0007]    In this way, the driving assist device according to the first aspect is accordingly capable of suppressing discomfort when a driver views an image of a blind spot region compared to a configuration in which an image is displayed on a display device provided to the vehicle component causing the blind spot. 
         [0008]    In the above aspect, a configuration may be provided, wherein the projection device comprises a display device that displays the image; and a reflective member positioned on a driver side of the vehicle component to reflect the image being displayed by the display device toward the driver. 
         [0009]    In such a driving assist device, the driver views the image captured by the imaging device as the virtual image by the reflective member reflecting the image displayed on the display device toward the driver side. This thereby enables the distance from the driver to the virtual image to be made the same as, or greater than, the sum of the distance from the display device to the reflective member, and the distance from the reflective member to the driver. As a result, a projection device that is able to exhibit the above function is configured using a simple structure. 
         [0010]    In the above aspect, a configuration may be provided, wherein the projection device further comprises an image enlargement device that is provided between the display device and the reflective member, and that enlarges the image being displayed by the display device. 
         [0011]    In such a driving assist device, the display image of the display device is enlarged by the image enlargement device, and the image enlarged by the image enlargement device is reflected by the reflective member toward the driver. Thus a distance from the driver to the virtual image can be secured even in a configuration with a short distance from the display device to the reflective member. 
         [0012]    In the above aspect, a configuration may be provided, wherein the display device and the image enlargement device are disposed inside a vehicle interior member. 
         [0013]    Such a driving assist device enables the projection device to be installed to a vehicle neatly since, out of the elements configuring the projection device, the display device and the image enlargement device are disposed inside the interior member. 
         [0014]    In the above aspect, a configuration may be provided, wherein the projection device is configured such that a distance from the driver to the virtual image is 1.5 m or greater. 
         [0015]    Due to the distance (viewing distance) from the driver to the virtual image being 1.5 m or greater, this driving assist device enables discomfort to a driver when viewing the image of the blind spot to be suppressed compared to cases in which the viewing distance is less than 1.5 m. 
       Advantageous Effects of Invention 
       [0016]    As explained above, the driving assist device according to the present invention exhibits the excellent advantageous effect of enabling discomfort to a driver when viewing an image of a blind spot to be suppressed. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0017]      FIG. 1  is a plan view schematically illustrating an overall configuration of a driving assist device according to a first exemplary embodiment. 
           [0018]      FIG. 2  is a side view schematically illustrating an overall configuration of a driving assist device according to the first exemplary embodiment. 
           [0019]      FIG. 3  is a schematic plan view to explain the layout of a display and mirror structure configuring a driving assist device according to the first exemplary embodiment. 
           [0020]      FIG. 4  is a side view schematically illustrating an overall configuration of a driving assist device according to a second exemplary embodiment. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0021]    Explanation follows regarding a visual information aid device  10  that is an example of a driving assist device according to the first exemplary embodiment of the present invention, with reference to the drawings. Note that in each of the drawings, the arrow FR, the arrow UP, the arrow RH, and the arrow LH respectively indicate the front direction, up direction, right direction and left direction when facing forward, for a vehicle installed with the visual information aid device  10 . In the following, unless otherwise stated, reference simply to front-rear, up-down, and left-right refers to the front-rear of the vehicle front-rear direction, the up-down of the vehicle up-down direction, and the left and right when facing forward. 
         [0022]    Vehicle General Configuration 
         [0023]    As illustrated in  FIG. 1 , a driver seat  12  and a front passenger seat  14  are provided within a cabin C of a vehicle V to which the visual information aid device  10  is applied. In this exemplary embodiment, the driver seat  12  is placed on the right side of the vehicle width direction center of the vehicle V. A windshield glass  16  and an instrument panel  18  are disposed in front of the driver seat  12 . Side window glass  20  is disposed at the respective vehicle width direction outsides of the driver seat  12  and the front passenger seat  14 . 
         [0024]    A front pillar  22  (and a door frame, not illustrated in the drawings) is disposed respectively between the left and right side window glass  20  and the windshield glass  16 . The left and right front pillars  22  correspond to a vehicle component that generates (causes) a blind spot for an occupant seated on the driver seat  12 , namely the driver D. 
         [0025]    Visual Information Aid Device 
         [0026]    The visual information aid device  10  is configured to display to the driver D visual information of a vehicle-outside region that configures a blind spot for the driver D. Specific explanation follows. 
         [0027]    As illustrated in  FIG. 1  and  FIG. 2 , the visual information aid device  10  is configured including a CCD camera  24  serving as an imaging device, a display  26  serving as a display device, and a mirror structure  28  serving as a reflective member. Pairs of the CCD camera  24 , the display  26  and the mirror structure  28  are respectively provided on the left and right sides. In the following explanation, the suffix “R” is added to the reference numeral for the right side, and the suffix “L” is added to the reference numeral for the left side when discriminating between the left and right CCD cameras  24 , displays  26 , and mirror structures  28 . 
         [0028]    The right side CCD camera  24 R is provided with its imaging direction aligned in plan view with a sight line direction Dgr from the driver D toward the right side front pillar  22  side, so as to capture images of a region diagonally forward and to the right of the cabin C. The left side CCD camera  24 L is provided with its imaging direction aligned in plan view with a sight line direction Dgl from the driver D toward the left side front pillar  22  side, so as to capture images of a region diagonally forward and to the left of the cabin C. The left and right CCD cameras  24  are, for example, disposed inside corresponding door mirror devices  32  on the respective left and right sides. 
         [0029]    The right side display  26 R is configured for either wireless or wired input of image data from the CCD camera  24 R, so as to display an image based on the image data. The display  26 R is, for example, provided in the cabin C at the width direction outside of the driver seat  12  (at the side of a seatback  12 A configuring the driver seat  12  in the present exemplary embodiment), with the display screen facing forward. 
         [0030]    The left side display  26 L is configured for either wireless or wired input of image data from the CCD camera  24 L, so as to display an image based on the image data. The display  26 L is, for example, provided in the cabin C at the vehicle width direction outside of the front passenger seat  14  (at the side of a seatback  14 A configuring the driver seat  14  in the present exemplary embodiment), with the display screen facing forward. 
         [0031]    The right side mirror structure  28 R is provided along the right side front pillar  22  (pillar garnish, not illustrated in the drawings), so as to reflect the image displayed on the display  26 R toward the driver D. As a result of this, a configuration is provided in which the driver D is able to view the image captured by the CCD camera  24 R as a virtual image. In this exemplary embodiment, the display  26 R and the mirror structure  28 R configure a projector device  30  (the right side projector device  30 R) serving as a projection device. The projector device  30 R is configured to project such that the driver D views an image captured by the CCD camera  24 R as a virtual image positioned further to the vehicle outside than the front pillar  22 . 
         [0032]    More specifically, the projector device  30  is configured as illustrated in  FIG. 3 , such that the distance of the sum of a distance L 1  from the display  26 R to the mirror structure  28 R, and a distance L 2  from the mirror structure  28 R to the driver D, matches a viewing distance Lr from the driver D to the virtual image Vir. The display  26 R and the mirror structure  28 R are disposed such that the viewing distance Lr along the sight line direction Dgr is a sufficiently long distance with respect to the distance from the driver D to the right side front pillar  22 . This thereby enables the driver D to view the virtual image Vir as an image positioned at a position Pr at the vehicle outside. 
         [0033]    Similarly, the display  26 L and the mirror structure  28 L on the left side configure a left side projector device  30 L (projector device  30 ). Namely, the left side mirror structure  28 L is provided along the left side front pillar  22  (pillar garnish, not illustrated in the drawings) so as to reflect the image displayed on the display  26 L toward the driver D. As a result of this, a configuration is provided in which the driver D is able to view the image captured by the CCD camera  24 L as a virtual image. 
         [0034]    More specifically, the projector device  30 L is configured such that the distance of the sum of a distance L 3  from the display  26 L to the mirror structure  28 L, and a distance L 4  from the mirror structure  28 L to the driver D, matches a viewing distance L 1  from the driver D to the virtual image Vil. The display  26 L and the mirror structure  28 L are disposed such that the viewing distance L 1  along the sight line direction Dgl is a sufficiently long distance with respect to the distance from the driver D to the left side front pillar  22 . This thereby enables the driver D to view the virtual image Vil as an image positioned at a position P 1  at the vehicle outside. 
         [0035]    In this exemplary embodiment the viewing distances L 1 , Lr configured by the left and right projector devices  30 L,  30 R from the driver to the virtual images Vil, Vir are both 1.5 m or greater. 
         [0036]    Operation 
         [0037]    Explanation next follows regarding operation of the first exemplary embodiment. Note that in the following explanation, the left and right virtual images Vir, Vil, and the viewing distances Lr, L 1 , are referred to respectively as the virtual images Vi and the viewing distances L when there is no discrimination made in the explanation. 
         [0038]    First, the driver D of the vehicle V installed with the visual information aid device  10  drives the vehicle V whilst checking safety based on visual information viewed through the windshield glass  16  and the left and right side window glass  20 . 
         [0039]    In the visual information aid device  10 , images captured by the left and right CCD cameras  24  are projected by the projector devices  30  to be viewed by the driver D as the virtual images Vi positioned diagonally in front of the front pillars  22  at positions at the vehicle outside. Namely, actual vehicle external scene s (visual information) of regions where blind spots are formed by the front pillars  22  are projected onto the mirror structures  28  provided to the front pillars  22  as virtual images Vi, thereby enabling the driver D to face in the direction to be checked (the blind spot direction) to view images that supplement the blind spot regions. This thereby enables the driver to notice a pedestrian W in cases in which the pedestrian W is present in a vehicle-outside region where a blind spot is present, such as for example illustrated in  FIG. 1 . 
         [0040]    For example, in a Comparative Example in which a driver D views an image displayed on a screen of a display device disposed along the front pillar  22 , the viewing distance from the driver D to the display image is about the same as the distance L 2  from the driver D to the mirror structure  28  in the present exemplary embodiment. In the Comparative Example, there is therefore a large perspective difference between the viewing distance to the actual vehicle external scene (for example 2 m) and the viewing distance to the displayed image. This results in the driver D needing to match (adjust) their focal point to the display image when switching from viewing the actual vehicle external scene to viewing the display image, with a tendency for this to impart discomfort to the driver D. 
         [0041]    In contrast thereto, in the visual information aid device  10  according to the present exemplary embodiment, images captured by the CCD cameras  24  are viewed by the driver D as virtual images Vi at positions outside the vehicle. There is accordingly a smaller difference in viewing distance between the viewing distance (for example 2 m) to the actual vehicle external scene and the virtual images Vi viewed by the driver D than in the Comparative Example described above, making the driver D less liable to experience discomfort in focal point adjustment to the virtual images Vi. 
         [0042]    In this way, the visual information aid device  10  according to the first exemplary embodiment accordingly suppresses discomfort when the driver D views an image of the blind spot region caused by the front pillar  22  compared to a configuration in which a display device is provided to the front pillar  22  that forms the blind spot. 
         [0043]    In particular, due to setting the viewing distances Lr, L 1  from the driver D to the virtual images Vi at 1.5 m or greater, the time required by the driver D for focal point adjustment to the virtual images Vi is shortened. It has, for example, been confirmed that when shifting sight line from the actual vehicle external scene to the virtual images Vi, focal point adjustment to the virtual images Vi can be performed in hardly any time even for a driver of 45 years of age or above. In other words, it is possible for the driver D to match to the focal points of both the actual vehicle external scene and the virtual images Vi (at the same time). 
         [0044]    The visual information aid device  10  thereby effectively suppresses discomfort when the driver D views the respective blind spot regions caused by the front pillars  22  as the virtual images Vi, compared to a configuration in which the viewing distances Lr, L 1  from the driver D to the virtual images Vi are less than 1.5 m. 
         [0045]    Moreover, in the visual information aid device  10 , the images displayed on each of the displays  26  are reflected by the mirror structure  28  for the driver D to view as the virtual images Vi. As a result, the projector device  30  that is able to exhibit the above function is configured using a simple structure. 
       Second Exemplary Embodiment 
       [0046]    Explanation next follows regarding a visual information aid device  50  serving as another example of a driving assist device according to a second exemplary embodiment of the present invention, with reference to  FIG. 4 . Note that configuration that is basically the same as that of the first exemplary embodiment configuration is allocated the same reference numerals as the configuration of the first exemplary embodiment, and further explanation and illustration thereof is omitted. Left and right CCD cameras  24  and projection devices  52  configuring the visual information aid device  50  are configured with basically left-right symmetry, except for the optical axis direction, and so the singular form is used in the following explanation without particular discrimination between left and right. 
         [0047]    The visual information aid device  50  is configured with main parts of the CCD camera  24  and the projection device  52 . The projection device  52  is configured with main parts of a display  54 , an image magnifying lens  56  serving as an image enlargement device, and a mirror structure  28 . 
         [0048]    The display  54  is configured with a smaller display screen that that of the display  26  in the first exemplary embodiment, and has a configuration with a smaller physical size than that of the display  26 . The image magnifying lens  56  is an optical member with a function to optically magnify the image being displayed on the display  54 , and a function to reflect the image toward the mirror structure  28 . 
         [0049]    The display  54  and the image magnifying lens  56  are disposed inside an instrument panel  18  that serves as a vehicle interior member. The sum of a distance L 5  from the display  54  to the image magnifying lens  56 , and a distance L 6  from the image magnifying lens  56  to the mirror structure  28  is shorter than the distance L 1  from the display  26  to the mirror structure  28  in the first exemplary embodiment. 
         [0050]    A viewing distance L from the driver D to the virtual image Vi in the present exemplary embodiment is given by (a distance equivalent to) the sum of a corrected distance obtained by multiplying the distance L 5  by a magnification power A of the image magnifying lens  56  (=L 5 ×A), and the above distance L 6  and the distance L 2 . 
         [0000]        L=L 5× A+L 6+ L 2
 
         [0051]    The disposition of the display  54 , the image magnifying lens  56 , and the mirror structure  28  configuring the projection device  52 , and the magnification power A of the image magnifying lens  56 , are set such that the viewing distance L (each of the left and right viewing distances Lr, L 1 ) is 1.5 m or greater. Other configuration of the visual information aid device  50 , including non-illustrated portions, is configured similarly to corresponding configuration in the visual information aid device  10  according to the first exemplary embodiment. 
         [0052]    Therefore, the visual information aid device  50  according to the second exemplary embodiment is also capable of obtaining basically the same advantageous effects by operation similar to that of the visual information aid device  10  according to the first exemplary embodiment. In the visual information aid device  50 , the image magnifying lens  56  also magnifies the display image of the display  54 , and reflects the magnified image toward the driver D side using the mirror structure  28 . This thereby enables the viewing distance from the driver D to the virtual image Vi to be secured even in configuration in which there is a short distance from the display  54  to the mirror structure  28 . 
         [0053]    Use of a display  54  with a small display screen, namely a small physical size, is thereby enabled. Moreover, due to the image magnifying lens  56  having an image reflecting function, there are fewer restrictions on the placement of the display  54  than in a configuration with direct reflection of the display  54  image by the mirror structure  28 . Thus in the present exemplary embodiment, the display  54  and the image magnifying lens  56  configuring the projection device  52  are disposed inside the instrument panel  18 . Thus with the exception of the mirror structure  28 , the visual information aid device  50  including the projection device  52  can be mounted more neatly to the vehicle V than the visual information aid device  10 , in which the display  26  is exposed inside the cabin C. 
         [0054]    Note that although, in each of the above exemplary embodiments, examples are given in which visual information of blind spot regions caused by front pillars  22  is used to provide assistance as the virtual images Vi, the present invention is not limited thereto. In the present invention, the visual information that the driver views as virtual images may be any visual information, as long as it is visual information of a blind spot region of the driver D caused by a vehicle component. Thus, for example, the visual information aid device may be configured to capture an image of a vehicle external (or cabin C external) region where there is a blind spot caused by a fender or front hood, and to project the captured image onto a mirror structure provided to the instrument panel. Moreover, for example, the visual information aid device maybe configured to capture visual information where there is a blind spot to the rear (when reversing), such as that caused by a rear seat back or rear pillar, a rear fender, or a rear door, and to project the captured visual information onto the rear pillar or a mirror structure provided at the rear pillar or the like. 
         [0055]    Moreover, although in each of the above exemplary embodiments examples have been given in which the CCD cameras  24  are employed as imaging device, the present invention is not limited thereto, and any imaging device may be employed. A CMOS camera or the like may accordingly be employed, for example, in place of the CCD camera  24 . 
         [0056]    Moreover, in each of the above exemplary embodiments examples are given in which the CCD cameras  24  and the projector devices  30 ,  52  are provided at both the left and right, however the present invention is not limited thereto. For example, configuration may be made with the CCD camera  24  and the projector device  30 ,  52  provided only on one side out of the left or right. 
         [0057]    Moreover, in the second exemplary embodiment, an example is given in which the display  54  and the image magnifying lens  56  configuring the projection device  52  are disposed in the instrument panel  18 , however the present invention is not limited thereto. For example, configuration may be made with the display  54  and the image magnifying lens  56  disposed inside a roof trim or door trim. 
         [0058]    Moreover, in the present invention, obviously various modifications may be implemented within a range not departing from the spirit of the present invention. For example, configurations may be employed that are appropriate combinations of configuration features of each of the exemplary embodiments and modified embodiments.
     10  visual information aid device (driving assist device)     22  front pillar (vehicle component)     24  CCD camera (imaging device)     26  display (display device, projection device)     28  mirror structure (reflective member, projection device)     30  projector device (projection device)     50  visual information aid device (driving assist device)     52  projection device (projection device)     54  display (display device, projection device)     56  image magnifying lens (image enlargement device, projection device)