Patent Publication Number: US-2002012047-A1

Title: Vehicle periphery visual confirming apparatus

Description:
BACKGROUND OF THE INVENTION  
       [0001] 1. Field of the Invention  
       [0002] The present invention relates to a vehicle periphery visual confirming apparatus which, under a poor visibility condition, takes a picture of a peripheral scene before or behind a vehicle, or, on the right- or left-side scene of the vehicle, that is, the scene of a blind spot to a driver and displays the picture of the scene to the driver.  
       [0003] 2. Description of the Related Art  
       [0004] A conventional vehicle periphery visual confirming apparatus  1 , as shown in FIG. 2 and  7 , comprises a picture camera apparatus  11  disposed on a front bumper  17  of a vehicle  16  to take pictures of the two side scenes of the vehicle  16 , a mirror image reversal processing part  12  for mirror-image processing picture signals supplied from the picture camera apparatus  11 , and a display part  15  disposed with in a vehicle room for displaying the picture images obtained from the mirror image reversal processing part  12 .  
       [0005] The picture camera apparatus  11  comprises: a lightproof case  3  on the two sides of which there are formed a pair of left and right penetration window portions  2 L,  2 R; a prism  4  having an isosceles-triangular-shaped section stored in the interior portion of the case  3  and disposed in such an attitude that its vertical angle portion  5  faces the front portion of the case  3  and its left and right prism side surfaces  8 L,  8 R respectively face the left and right penetration window portions  2 L,  2 R; and, an imaging device  10  stored and disposed in the rear of the rear surface  8 B of the prism  4  through an imaging lens  9 .  
       [0006] In this structure, light rays  18 L, which have entered from the penetration window portion  2 L and have penetrated through the prism side surface  8 L, are reflected by the internal surface of the other prism side surface  8 R and are then guided through the imaging lens  9  onto the left half surface  10 L of the imaging surface of the imaging device  10 . On the other hand, light rays  18 R, which have entered from the penetration window portion  2 R and have penetrated through the prism side surface  8 R, are reflected by the internal surface of the other prism side surface  8 L and are then guided through the imaging lens  9  onto the right half surface  10 R of the imaging surface of the imaging device  10 . That is, the pictures of the two right- and left-side scenes can be taken at the same time by the imaging device  10 .  
       [0007] And, the image signals of the pictures of the scenes taken by the imaging device  10  are mirror-image-reversal processed by the mirror image reversal processing part  12  and are then output to the display part  15 ; and, the left-side scene introduced from the penetration window portion  2 L into the left half screen  15 L of the display part  15  is displayed as the left-side scene images, whereas the right-side scene introduced from the penetration window portion  2 R into the right half screen  15 R of the display part  15  is displayed as the right-side scene images.  
       [0008] However, actually, as shown in FIG. 7, in the light rays  18 R which have entered the vertical angle adjacent area  5 R of the prism side surface  8 R, there exist light rays such as light rays  18 Ra which, after they are reflected by the internal surface of the prism side surface  8 L and are penetrated through the imaging lens  9 , are not guided to the right half surface  10 R of the imaging surface of the imaging device  10  but are guided to a boundary area  10 La on the left half surface  10 L side. In this case, the light rays  18 R of the right-side scene are taken in from the penetration window portion  2 L by the imaging device  10  and are mingled with the light rays  18 L of the left-side scene guided to the same boundary area  10 La, before they are converted into image signals. And, in a boundary area  10 Ra on the right half surface  10 R side of the imaging surface as well, because they are symmetric, there occurs a similar phenomenon.  
       [0009] As a result of this, there arises the following problem: that is, the images to be displayed on the display part  15 , as shown in FIG. 9, are displayed in the screen central portion  23  of the display part  15  in such a manner that the left-side scene images  19 L and right-side scene images  19 R are overlapped with each other.  
       SUMMARY OF THE INVENTION  
       [0010] The present invention aims at eliminating the above drawbacks found in the conventional vehicle periphery visual confirming apparatus. Accordingly, it is an object of the invention to provide a vehicle periphery visual confirming apparatus capable of preventing one-side scene images and the-other-side scene images from being displayed in such a manner that they are overlapped together in the central portion of the display screen.  
       [0011] In attaining the above object, according to a first aspect of the invention, there is provided a vehicle periphery visual confirming apparatus comprising a picture camera apparatus disposed on the outside of a vehicle, the picture camera apparatus comprising: a case including a pair of right and left penetration window portions respectively formed on the two sides thereof; a prism having an isosceles-triangular-shaped section and disposed within the case in such an attitude that its vertical angle portion faces the front portion of the case and its right and left prism side surfaces corresponding to the two equal sides of its isosceles triangle shape respectively face the right and right penetration window portions; an imaging lens disposed in the rear of the prism rear surface; and, an imaging device which is disposed in the rear of the imaging lens and also which, when light rays entering from one of the right and left prism side surfaces are reflected by the other of the right and left prism side surfaces and are radiated from the prism rear surface of the prism, focuses the light rays onto an imaging surface of the imaging device through the imaging lens to thereby convert the light rays into image signals, characterized by preventive means which is disposed in the vertical angle portion of the prism and also which, when light rays penetrate through one of the penetration window portions and one of the vertical angle adjacent areas of the prism side surfaces sequentially, are reflected by the internal surface of the other-side prism side surface, are radiated from the prism rear surface, and are focused through the imaging lens onto the other-side half surface area of the imaging surface of the imaging device, can be prevent such light rays from advancing into the prism through the vertical angle adjacent areas of the two prism side surfaces.  
       [0012] According to a second aspect of the invention, in a vehicle periphery visual confirming apparatus as set forth in the first aspect of the invention, the preventive means is means formed by chamfering the vertical angle portion of the prism in such a manner that the vertical angle adjacent areas of the two prism side surfaces are cut away from the prism.  
       [0013] According to a third aspect of the invention, in a vehicle periphery visual confirming apparatus as set forth in the first aspect of the invention, the preventive means is a light shielding member disposed in the vertical angle adjacent areas of the two prism side surfaces so as to cover them.  
       [0014] According to a fourth aspect of the invention, in a vehicle periphery visual confirming apparatus as set forth in the third aspect of the invention, the light shielding member is formed integral with the case.  
       [0015] According to a fifth aspect of the invention, in a vehicle periphery visual confirming apparatus as set forth in the third aspect of the invention, the light shielding member is formed integral with a prism fixing member for fixing the prism to the case. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0016]FIG. 1 is a schematic view of the structure of a vehicle periphery visual confirming apparatus according to a first embodiment of the invention;  
     [0017]FIG. 2 is a view of a state of a vehicle on which there is disposed a picture camera apparatus forming a part of a vehicle periphery visual confirming apparatus according to the first embodiment of the invention;  
     [0018]FIG. 3 is a schematic view of the structure of a vehicle periphery visual confirming apparatus according to the second embodiment of the invention;  
     [0019]FIG. 4 is an enlarged view of the vertical angle adjacent portion of a prism forming a part of a vehicle periphery visual confirming apparatus according to a second embodiment of the invention;  
     [0020]FIG. 5 is an exploded perspective view of a picture camera apparatus forming a part of a vehicle periphery visual confirming apparatus according to a third embodiment of the invention;  
     [0021]FIG. 6 is an enlarged view of the vertical angle adjacent portion of a prism forming a part of a vehicle periphery visual confirming apparatus according to the third embodiment of the invention;  
     [0022]FIG. 7 is a schematic view of the structure of a conventional vehicle periphery visual confirming apparatus;  
     [0023]FIG. 8 is an explanatory view of a display state of a display screen in a vehicle periphery visual confirming apparatus according to the invention; and  
     [0024]FIG. 9 is an explanatory view of a display state of a display screen in a conventional vehicle periphery visual confirming apparatus. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0025] Now, a description will be given in more detail of preferred embodiments of the invention with reference to the accompanying drawings.  
     [0026] (First Embodiment)  
     [0027] Now, description will be given below of a first embodiment of a vehicle periphery visual confirming apparatus according to the invention with reference to FIGS. 1 and 2. FIG. 1 is a schematic view of the structure of a vehicle periphery visual confirming apparatus according to the first embodiment of the invention, and FIG. 2 is a view of a state of a vehicle on which there is disposed a picture camera apparatus forming part of the present vehicle periphery visual confirming apparatus, showing a state in which the picture camera apparatus is disposed in a vehicle.  
     [0028] The vehicle periphery visual confirming apparatus  1 A according to the present embodiment, as shown in FIGS. 1 and 2, comprises a picture camera apparatus  11 A which is to be disposed on the outside portion of a vehicle  16 , for example, on a front bumper  17  or a front grille thereof, a mirror image reversal processing part  12  which mirror image reversal processes the signal of the image taken by the picture camera apparatus  11 A, and a display part  15  composed of an LCD or a CRT which is disposed on a dashboard within a vehicle chamber so as to be able to output and display the image signals that have been processed by the mirror image reversal processing part  12 .  
     [0029] The picture camera apparatus  11 A comprises: a lightproof case  3 A including a pair of left and right penetration window portions  2 L,  2 R which are formed of glass or plastic and are respectively formed on the two side surfaces of the case  3 A; a prism  4  disposed within the case  3 A and formed as a prismatic body having an isosceles-triangular-shaped section; an imaging lens  9  disposed within the case  3 A; and, an imaging device  10  disposed within the case  3 A and including a CCD camera.  
     [0030] The prism  4  is disposed in the interior portion of the case  3 A, while it is fixed, for example, by a prism fixing member  32 , in such an attitude that the vertical angle portion  5  thereof faces the front portion of the case  3 A and the prism side surfaces  8 L,  8 R thereof face the penetration window portions  2 L,  2 R of the case  3 A.  
     [0031] Here, the prism fixing member  32  not only has a function to hold the prism  4  from right and left so as to cover the respective rear side areas (in FIG. 1, the lower areas) of the prism side surfaces  8 L,  8 R but also a function to shield the unnecessary light rays that enter the rear side areas of the prism side surfaces  8 R,  8 L (in FIG. 1, the lower areas of the prism side surfaces  8 R,  8 L) but do not constitute the right- and left-side scenes.  
     [0032] Also, the vertical angle portion  5  of the prism  4  is chamfered in the chamfer dimension that the vertical angle adjacent areas  5 L,  5 R of the prism side surfaces  8 R,  8 L are cut away, and a surface  5   a  formed by this chamfering operation is processed so as to provide a rough surface (a frosted-glass-like surface) in order to be able to prevent the light rays from entering the interior portion of the prism  4  from the chamfered surface  5   a  (such treatment is referred to as a chamfering operation).  
     [0033] Here, the range of the vertical angle adjacent areas  5 R ( 5 L) to be cut away is specified in the following manner: that is, of the prism side surface  8 R ( 8 L), a range through which light rays  18 R ( 18 L) pass; by the way, the light rays  18 R ( 18 L), as shown in FIG. 7, enter the interior portion of the prism  4  from one prism side surface  8 R ( 8 L), are reflected by the internal surface of the other prism side surface  8 L ( 8 R), and are guided through the imaging lens  9  onto the left half surface  10 L (right half surface  10 R) of the imaging surface of the imaging device not onto the right half surface  10 R (left half surface  10 L) thereof.  
     [0034] And, the imaging lens  9  is fixed by a lens holder  26  in such a manner that, in the rear of the prism  4  (in FIG. 1, in the lower portion thereof), the optical axis  25  of the imaging lens  9  is coincident with the bisector of the vertical angle portion  5  of the isosceles-triangular-shaped section of the prism  4 . And, the imaging device  10  is fixed in such a manner that, in the rear of the imaging lens  9 , the imaging surfaces  10 L,  10 R are parallel to the prism rear surface  8 B and the center  30  of the boundary line between the left and right half surfaces  10 L and  10 R of the imaging surface is present on the optical axis  25 . By the way, in this structure, the prism side surfaces  8 L,  8 R are disposed symmetric with respect to the optical axis  25 .  
     [0035] That is, by chamfering the vertical angle portion  5  of the prism  4  in the above-mentioned manner, for example, of the light rays  18 R that correspond to the right-side scene, light rays (not shown in FIG. 1) passing through a portion where the vertical angle adjacent area  5 R was once present, such as the light rays  18 Ra shown in FIG. 7, pass in front of the chamfered surface  5   a  (in FIG. 1, upwardly of the chamfered surface  5   a ) and go to the outside through the penetration window portion  2 L, or enter the surface  5   a , are scattered by the rough surface of the surface  5   a , so that they are prevented from advancing into the prism  4 . On the other hand, the light rays  18 R entering the other areas of the prism side surface  8 R than the vertical angle adjacent area  5 R thereof penetrate through the transparent window portion  2 R and prism side surface  8 R sequentially, are reflected by the internal surface of the prism side surface  8 L, are radiated from the prism rear surface  8 B, and are guided through the imaging lens  9  onto the right half surface  10 R of the imaging surface of the imaging device  10 .  
     [0036] In the case of the light rays  18 L that correspond to the left-side scene, as the light rays  18 L and  18 R are symmetric, similarly to the light rays  18 R, the light rays  18 L are not guided onto the right half surface  10 R of the imaging surface of the imaging device  10  but are guided onto the left half surface  10 L thereof. In this manner, the right- and left-side scenes are photographed at the same time by the picture camera apparatus  11 A.  
     [0037] And, the light rays  18 R and  18 L, which have been guided onto the right half surface  10 R and left half surface  10 L of the imaging surface of the imaging device  10  respectively, are converted into image signals by the imaging device  10 , are mirror image reversal processed by the mirror image reversal processing part  12 , and are then output to the display part  15 . And, in the display part  15 , as shown in FIG. 8, the left-side scene photographed through the penetration window portion  2 L is displayed as left-side scene images  19 L in the left half screen  15 L of the display part  15 , whereas the right-side scene photographed through the penetration window portion  2 R is displayed as right-side scene images  19 R in the right half screen  15 R of the display part  15 .  
     [0038] According to the above-structured vehicle periphery visual confirming apparatus  1 A, because the vertical angle portion  5  of the prism  4  is chamfered in such a manner that the vertical angle adjacent areas  5 L,  5 R thereof are cut away and the chamfered surface  5   a  is processed so as to provide a rough surface, the light rays  18 R ( 18 L) entering the portion where the vertical angle adjacent area  5 R ( 5 L) was once present pass through the chamfered surface  5   a  and go to the outside through the penetration window portion  2 L ( 2 R), or, they enter the chamfered surface  5   a , are scattered by the rough surface of the chamfered surface  5   a , whereby they are prevented from advancing into the prism  4 . This can prevent occurrence of a phenomenon that the light rays  18 R ( 18 L) corresponding to the right-side (left-side) scene advance into the prism  4  through the vertical angle adjacent area  5 R ( 5 L), are reflected by the internal surface of the other prism side surface  8 L ( 8 R), and are then guided onto the left half surface  10 L ( 10 R) of the imaging device  10  which is the imaging surface for the opposite-side scene. Therefore, in the display part  15 , as shown in FIG. 8, the left-side scene images  19 L corresponding to the left-side scene are displayed on the left half screen  15 L in such a manner that the images are not overlapped in the central portion of the screen, while the right-side scene images  19 R corresponding to the right-side scene are similarly displayed on the right half screen  15 R. This makes it possible to supply a driver with a vehicle peripheral scene picture which is easy to confirm visually.  
     [0039] By the way, in the present embodiment, description has been given on the assumption that the picture camera apparatus  11 A is disposed on the front bumper  17  or front grille of the vehicle  16  and the right-side and left-side scenes in front of the vehicle are photographed by the picture camera apparatus  11 A. However, this is not limitative but, alternatively, the picture camera apparatus  11 A may be disposed on a rear bumper of the vehicle  16  and the right-side and left-side scenes in the rear of the vehicle may be photographed by the picture camera apparatus  11 A. Of course, scenes before and behind the vehicle  16  may also be photographed.  
     [0040] (Second Embodiment)  
     [0041] Now, description will be given below of a second embodiment of a vehicle periphery visual confirming apparatus according to the invention with reference to FIGS. 3 and 4. FIG. 3 is a schematic view of the structure of a second embodiment of a vehicle periphery visual confirming apparatus according to the invention, and FIG. 4 is an enlarged section view of the vertical angle adjacent portion of a prism forming a part of the present vehicle periphery visual confirming apparatus. By the way, in FIGS. 3 and 4, the parts as those employed in the first embodiment are given the same designations and thus the description thereof is omitted here, while description will be given below of only the parts that are different from the first embodiment.  
     [0042] A picture camera apparatus  11 B according to the second embodiment, as shown in FIGS. 3 and 4, is almost similar in structure to the first embodiment, except for the following aspect: that is, in the first embodiment, the vertical portion  5  of the prism  4  is chamfered but, in the second embodiment, instead of such chamfering operation, a light shield portion (light shielding member)  3   a  is disposed so as to cover the vertical angle adjacent areas  5 L,  5 R of the prism side surfaces  8 L,  8 R.  
     [0043] The light shield portion  3   a  is formed integral with a case  3 A in such a manner that it is provided on and projected from the internal surface of the front portion of the case  3 A. And, the leading end portion of the light shield portion  3   a , as shown in FIG. 4, is formed in a V-shaped recess having the same angle as the vertical angle of the vertical angle portion  5  of the prism  4 ; and, here, it is formed so as to be able to cover only the vertical angle adjacent areas  5 L,  5 R specified in the first embodiment. By the way, preferably, the leading end portion of the light shield portion  3   a  may be formed so as to cover only the vertical angle adjacent areas  5 L,  5 R. However, the leading end portion of the light shield portion  3   a  may also be formed so as to cover the range that includes the vertical angle adjacent areas  5 L,  5 R.  
     [0044] Since the light shield portion  3   a  is formed so as to cover the vertical angle adjacent areas  5 L,  5 R of the prism side surfaces  8 L,  8 R, of the light rays  18 R ( 18 L) that correspond to the right-side scene, the light rays entering the vertical angle adjacent area  5 R ( 5 L) like the light rays  18 Ra ( 18 La) shown in FIG. 7, as shown in FIG. 4, are shielded by the light shield portion  3   a  and are thereby prevented from entering the interior portion of the prism  4 . Therefore, it is possible to prevent a phenomenon occurring in the conventional vehicle periphery visual confirming apparatus that the light rays  18 R ( 18 L) corresponding to the right-side (left-side) scene enter through the vertical angle adjacent area  5 R ( 5 L) into the prism  4 , are reflected by the internal surface of the other prism side surface  8 L ( 8 R), and are guided onto the left half surface  10 L (right half surface  10 R) of the imaging device  10  which is the imaging surface for the opposite-side scene.  
     [0045] By the way, in the case of the light rays  18 R,  18 L which enter the other areas of the prism side surfaces  8 R,  8 L than the vertical angle adjacent areas  5 R,  5 L, they are processed similarly to the first embodiment and thus the description thereof is omitted here.  
     [0046] In the above-structured vehicle periphery visual confirming apparatus  1 B as well, there can be provided a similar effect to the vehicle periphery visual confirming apparatus  1 A according to the first embodiment.  
     [0047] (Third Embodiment)  
     [0048] Now, description will be given below of a third embodiment of a vehicle periphery visual confirming apparatus according to the invention with reference to FIGS. 5 and 6. FIG. 5 is an exploded perspective view of a picture camera apparatus forming a part of a vehicle periphery visual confirming apparatus according to the third embodiment of the invention, and FIG. 6 is an enlarged section view of the vertical angle adjacent portion of a prism forming a part of the present picture camera apparatus.  
     [0049] A picture camera apparatus  11 C according to the present embodiment is structured almost similarly to the second embodiment except for the following aspect: that is, in the second embodiment, the light shield portion  3   a  is formed integral with the case  3 A but, in the third embodiment, as shown in FIG. 5, a light shield portion  3   a  is formed integral with a prism fixing member  32  for fixing a prism  4  to a case main body  3 Aa (which corresponds to the case  3 A). Therefore, in FIGS. 5 and 6, the same parts as those employed in the second embodiment are given the same designations and thus the description thereof is omitted here, while description will be given below of only the parts that are different from the second embodiment.  
     [0050] The prism fixing member  32  is made of a light shielding member and, as shown in FIG. 5, is composed of a combination of hold portions  32 L,  32 R for holding the prism  4  from right and left so as to cover the rear-side areas of the prism side surfaces  8 L,  8 R of the prism  4 , and hold portions  32 U,  32 D for holding the prism  4  from top and bottom so as to cover the upper and lower surfaces of the prism side surfaces  8 L,  8 R of the prism  4 .  
     [0051] The hold portions  32 L,  32 R are used not only to hold the prism  4  from right and left but also to shield the unnecessary light rays that enter the rear-side areas of the prism side surfaces  8 L,  8 R but do not form the right- and left-side scenes. By the way, on the outer surfaces of the hold portions  32 L,  32 R, there are provided projections  33  which can be fixedly connected to the case main body  3 Aa.  
     [0052] The light shield portion  3   a  (light shielding member) is formed as a light shielding rod body which is straddlingly interposed between the hold portions  32 U,  32 D of the prism fixing member  32  so as to cover the vertical angle portion  5  of the prism  4 . The surface of the light shield portion  3   a  for covering the vertical angle portion  5  of the prism  4  is formed in a V-shaped recess shape having the same angle along the longitudinal direction thereof as the vertical angle of the vertical portion of the prism  4 ; and, here, it is formed so as to cover only the vertical angle adjacent areas  5 L,  5 R specified in the first embodiment. By the way, preferably, the V-shaped recessed surface of the light shield portion  3   a  may be formed so as to cover only the vertical angle adjacent areas  5 L,  5 R. However, the V-shaped recessed surface of the light shield portion  3   a  may also be formed so as to cover the range that includes the vertical angle adjacent areas  5 L,  5 R.  
     [0053] In the case of the prism  4  with the prism fixing member  32  and light shield portion  3   a  mounted thereon, by fixing the projections  33  of the prism fixing member  32  to the internal surface of the case main body  3 Aa using screws, the prism  4  can be fixed to the interior portion of the case  3 A in such a manner that the vertical angle portion  5  thereof faces the front portion of the case main body  3 Aa and the prism side surfaces  8 L,  8 R thereof face the penetration window portions  2 L,  2 R of the case main body  3 Aa.  
     [0054] Here, imaging means  27  is composed of an imaging lens  9  and an imaging device  10  respectively disposed within a lens holder  26 . And, a rear case  3 Ab with the imaging means  27  mounted therein is mounted into the rear-side opening  35  of the case main body  3 Aa in such a manner that the imaging means  27  is stored in the case main body  3 Aa, thereby forming the picture camera apparatus  11 C. And, in case where the rear case  3 Ab is mounted into the rear-side opening  35  of the case main body  3 Aa, the case main body  3 Aa and rear case  3 Ab cooperate together in forming the case  3 A (see FIG. 1).  
     [0055] In the above-structured vehicle periphery visual confirming apparatus  1 C as well, there can be provided a similar effect to the vehicle periphery visual confirming apparatus  1 A according to the first embodiment.  
     [0056] According to the first to fifth aspects of the invention, the light rays (which penetrate through one of the penetration window portions and one of the vertical angle adjacent areas of the prism side surfaces sequentially, are reflected by the internal surface of the other-side prism side surface, are radiated from the prism rear surface, and are focused through the imaging lens onto the other-side half surface area of the imaging surface of the imaging device) can be prevented by the preventive means from advancing into the prism through the vertical angle adjacent areas of the two prism side surfaces. Also, according to the second aspect of the invention, the vertical angle portion of the prism is chamfered in such a manner that the vertical angle adjacent areas of the two prism side surfaces are cut away. Further, according to the third to fifth aspects of the invention, the light shield member is disposed on the vertical angle adjacent areas of the two prism side surfaces so as to cover these areas. Thanks to this, it is possible to prevent a phenomenon occurring in the conventional vehicle periphery visual confirming apparatus that the light rays penetrating through one of the penetration window portions enter the prism through the vertical angle adjacent area of the same-side prism side surface, are reflected by the internal surface of the other-side prism side surface, and are guided through the imaging lens onto the other-side half surface area of the imaging surface of the imaging device. Therefore, there is eliminated a possibility that the images to be essentially displayed in one-side half surface of the imaging surface of the imaging device can be guided into and displayed on the other-side half screen, and thus, when the images on the two sides are displayed on the display screen of the display part, can be prevented from being overlapped with each other in the central portion of the display screen. This makes it possible to supply a driver with good-visibility vehicle periphery images in which the images of the two side scenes are prevented from being overlapped together in the central portion of the display screen.