JP2006221366A - On-vehicle image pickup device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an on-vehicle image pickup device for reducing the components of stray lights of light as much as possible. <P>SOLUTION: This on-vehicle image pickup device is provided with a case 23 whose right and left side faces are respectively formed with transparent window parts 21R and 21L, an image pickup element arranged at the rear part of the case 23, an image pickup lens 29 housed in the case 23 for converging the rays of light to the image pickup element, a pair of right and left prisms 24b and 24a housed in the case 23 for reflecting the rays of light fetched from the right and left sides through the transparent window parts 21R and 21L to the optical system side and a prism fixing member 77 for holding prism side faces 65R and 65L faced to the transparent window parts 21R and 21L of the respective prisms 24b and 24a in parallel on the inside surfaces of the transparent window parts 21R and 21L. The prism side faces 65R and 65L are precisely formed in parallel on the inside surfaces of the transparent window parts 21R and 21L so that stray lights can be reduced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an in-vehicle image pickup apparatus applied to a vehicle periphery visual recognition device that monitors and displays multidirectional blind spot images around a vehicle on a display unit in a vehicle interior.

  As a technique for monitoring and displaying a blind spot image in front of left and right sides of a vehicle on a display device in a vehicle interior, there is one that uses only one image sensor (CCD) and images a blind spot image in front of left and right sides of the vehicle. As shown in FIG. 8, a prismatic body having a triangular cross-section is formed in a light-shielding case in which a pair of left and right substantially rectangular transparent windows (light transmission windows) 1 made of glass, plastic, or the like are provided on both left and right sides. The prism 2 formed in the above, an imaging lens disposed behind the prism 2, and an image pickup device composed of a CCD camera or the like disposed further behind the prism 2 are housed and arranged. When the light beam 3 taken into the case from the transparent window portion 1 enters the prism 2, the light beam 3 is internally reflected inside the prism 2, and the imaging lens and further image pickup from the rear surface of the prism 2. Guided to the element. At this time, the video imaged by the imaging device is electrically mounted on the display device in the passenger compartment and displayed on the monitor.

  Incidentally, the light beam 3 taken into the case from the transparent window portion 1 is light 3a incident on the prism side surface 5 (thick line in FIG. 8) and light 3b reflected by the prism side surface 5 (two-dot chain line in FIG. 8). ). Among these, the light 3 b reflected by the prism side surface 5 goes again to the transparent window portion 1 side facing the prism side surface 5. The light 3 b is reflected again by the inner surface 6 of the transparent window portion 1 and is incident on the prism side surface 5.

  At this time, if the inner surface 6 of the transparent window portion 1 and the prism side surface 5 are non-parallel, the light 3b reflected by the prism side surface 5 is reflected by the inner surface 6 of the transparent window portion 1 as shown in FIG. When the light is incident on the prism side surface 5 again, the incident angle is different from that of the light 3a, and the incident light 3b is displayed on the screen as stray light.

  The cause of such stray light is that the inner surface 6 and the prism side surface 5 of the transparent window portion 1 are non-parallel.

  However, conventionally, the prism side surface 5 and the surface of the transparent window portion 1 have not been accurately parallelized.

  Accordingly, an object of the present invention is to provide an in-vehicle imaging device that can reduce the stray light component as much as possible.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a case in which transparent windows are provided on both left and right side surfaces, an image pickup device disposed behind the case, and housed in the case. An optical system for condensing light with respect to the image sensor; a prism that is housed in the case and reflects light taken from the left and right sides through the transparent window portion toward the optical system; and each of the prisms And a prism fixing member that holds a prism side face facing the transparent window portion parallel to the inner surface of the transparent window portion.

  A second aspect of the present invention is the in-vehicle imaging device according to the first aspect, wherein the prisms are mounted in a pair of left and right.

  A third aspect of the present invention is the in-vehicle imaging device according to the first or second aspect, wherein the prism fixing member includes a pedestal that abuts an end portion of the rear surface of the prism, and upper and lower ends of the prism. And a holding body that contacts the front end portion of the prism and holds the prism.

  A fourth aspect of the present invention is the in-vehicle imaging device according to the third aspect, wherein an optical system holding member that holds the optical system, and a first for fixing the optical system holding member to the case The apparatus further includes fixing means and second fixing means for fixing the holding body to the optical system holding member.

  Since the in-vehicle imaging device of the invention according to any one of claims 1 to 4 can set the side surfaces of both prisms accurately and parallel to the inner surface of the transparent window portion, the light rays are transmitted to the transparent window portion. The light reflected by the prism surface when incident is further reflected on the inside of the transparent window, and is incident on the same path or parallel path as the original light when entering the prism. Accordingly, it is possible to reduce as much as possible the stray light component that is often generated because the prism side surface and the inner surface of the transparent window portion are non-parallel.

  In particular, when imaging with a single imaging device using a pair of prisms as in claim 2, it is more difficult to position both prisms than with a single prism, but both prisms can be easily fixed with a prism fixing member. There is an advantage that it is possible to perform positioning.

<Configuration>
FIG. 1 is an external perspective view showing an in-vehicle imaging device according to an embodiment of the present invention, and FIGS. 2 to 5 are perspective views showing a state during the assembly.

  This in-vehicle image pickup apparatus is installed at a predetermined position such as a front bumper or a front grill of a vehicle, and uses only one image pickup device (CCD) to pick up a blind spot image in front of the left and right sides of the vehicle, The present invention is applied to a vehicle periphery visual recognition device that displays a monitor on an indoor display unit.

  The vehicle-mounted imaging device has a light-shielding case 23 provided with a pair of left and right substantially rectangular transparent window portions (light transmission windows) 21L and 21R made of glass, plastic, or the like on both left and right sides. 23 includes a prism 24a, 24b, which is a pair of right and left triangular prisms, an imaging lens (optical system) 29, and an image sensor (not shown) including a CCD camera or the like. . The prisms 24 a and 24 b and the imaging lens 29 function as optical means for guiding the light that has entered from the transparent window portions 21 </ b> L and 21 </ b> R to the image sensor inside the case 23 in the vehicle interior direction.

  As shown in FIGS. 1 to 5, the case 23 is formed by fixing a rear case 41 and a front case 43 with screws 45 as fixing parts.

  As shown in FIGS. 2 to 5, the rear case 41 is formed in a box with an open front using a light-shielding aluminum material or the like, and a plurality of radiating fins 47 are formed outside the rear surface. Further, a through hole (not shown) is formed in the rear surface of the rear case 41. The through hole (not shown) is formed with a circular groove in a front view through which the distal end portion 49a of the wire harness 49 and the connector 49b at the distal end thereof are penetrated. The through hole is screwed into a screw groove 51 a (FIG. 2) of the flange-like lid 51 fixed to the body portion on the wire harness 49 side and is closed by the lid 51. Furthermore, screw through holes 55 through which screws 45 (FIG. 5) for fixing the front case 43 pass are formed in the four corners 59 in front view of the rear case 41, and for fixing the imaging lens 29. A screw hole 56 into which the screw (first fixing means) 46 is screwed is formed (FIGS. 2 and 3).

  As an external shape of the front case 43, as shown in FIG. 1 and FIG. 5, the front part is formed in a hollow body having a substantially isosceles triangle shape in plan view, and the rear surface is open. The front case 43 is integrally formed of a single material such as a resin including the transparent window portions 21L and 21R, and the surface of the portion excluding the transparent window portions 21L and 21R is painted so as to be opaque. Has been. The transparent window portions 21L and 21R are formed so as to be parallel to prism side surfaces 65L and 65R described later.

  Further, screw holes (not shown) for screwing screws 45 (see FIG. 5) are formed at the four corners of the rear surface portion of the front case 43 so as to face the rear surface side.

  As shown in FIG. 5, a frame-shaped seal member (packing) 61 made of rubber or the like for enhancing water tightness is sandwiched between the rear case 41 and the front case 43 as shown in FIG. Installed.

  As shown in FIGS. 4 and 6, the prisms 24a and 24b are formed in a substantially triangular prism shape that is a mirror image target. As shown in FIG. 6, the left (right) prism 24a (24b) has the apex angle 63 directed to the front side, and the left (right) prism side surface 65L (65R) is the left (right) transparent window portion. It faces 21L (21R), that is, it is directed in the lateral visual field direction. The prism rear surface 67 a (67 b) is disposed so as to face the imaging lens 29. The left (right) prism 24a (24b) has a left (right) prism side surface 65L (65R) and a prism rear surface 67a (67b) held on the transmission surface, while the right (left) prism side surface. On 69R (69L), a protective film 71 made of a black paint is further formed so as to cover the vapor deposition surface after a metal layer such as aluminum is vapor deposited so that the inner surface thereof becomes a reflection surface (mirror surface). ing.

  The imaging lens 29 is fixed by a lens holder 36 behind the prisms 24a and 24b.

  As shown in FIG. 3, screw through-holes 75 through which screws 46 for fixing the rear case 41 pass are formed in two opposite corners of the front corners 73 of the lens holder 36. As shown in FIG. 4, screw holes 81 into which screws (second fixing means) 79 for fixing a prism fixing member 77 to be described later are screwed are formed at the other two locations in the front corners 73 of the holder 36 as shown in FIG. 4. Is formed.

  The imaging element (not shown) is mounted on a circuit board 72 (FIG. 3) disposed behind the imaging lens 29 in the lens holder 36. The circuit board 72 is detachably connected to the connector 49b.

  In this embodiment, the prism fixing member 77 that holds the prism side surfaces 65L and 65R facing the transparent window portions 21L and 21R of the pair of prisms 24a and 24b in parallel with the inner surfaces of the transparent window portions 21L and 21R. Is further provided.

  As shown in FIGS. 4 and 6, the prism fixing member 77 is in contact with the ends of the prism rear surfaces 67a and 67b of both the prisms 24a and 24b and sets the angular position thereof. A holding body 85 is provided to hold the upper and lower end portions, the front end portion, and the side end portions of the prisms 24a and 24b so as to cover the prisms 24a and 24b in a state where the positions are set.

  As shown in FIGS. 4 and 6, the pedestal 83 is formed by projecting forward from the upper and lower sides of the frame 87 and the upper and lower ends of the prism rear surfaces 67a and 67b. A pair of tapered contact bases 89L and 89R that define the angular position by abutment are integrally formed. A groove 91 is formed between the abutment portions 89L and 89R to avoid interference with a rear end portion of a center piece 105 of a holding body 85 described later. Further, both side portions of the frame 87 of the pedestal 83 are formed as elastic elastic contact portions 82 by using a rubber member (rubber) or the like, and these elastic contact portions 82 are attached to the lens holder 36. It comes to contact.

  As shown in FIGS. 4 and 6, the holding body 85 is formed with a light-shielding resin so that the rear surface is open, and the front end plate 93 that regulates the positions of the front end portions of both prisms 24 a and 24 b and the front end plate 93 are provided. A side end plate 95 that is integrally connected to abut the rear end portions of the prism side surfaces 65L, 65R on the side facing the transparent window portions 21L, 21R of both prisms 24a, 24b, and a substantially isosceles triangle in plan view And an upper and lower plate 97 integrally connected to the front end plate 93 and the side end plate 95, and a frame-like base 99 integrally connected to the rear end portions of the side end plate 95 and the upper and lower plates 97. Prepare.

  The side end plate 95 is formed with an open window frame 101 for the prism side surfaces 65L and 65R to face the transparent window portions 21L and 21R.

  As shown in FIG. 4, screw through holes 103 through which screws 79 for fixing the lens holder 36 pass are formed in the left and right ends of the base 99.

  Further, as shown in FIG. 6, a central piece 105 is formed at the central portion of the holding body 85 in the left-right direction so as to contact and position the prism side surfaces 69L and 69R on the inward side of the prisms 24a and 24b. ing.

  Note that reference numeral 107 in FIG. 2 indicates a heat dissipation sheet, and reference numeral 109 in FIG. 5 indicates a desiccant.

<Assembly method>
A method for assembling the in-vehicle imaging device having the above configuration will be described. First, as shown in FIG. 2, the front end portion 49 a of the wire harness 49 to which the connector 49 b is attached is passed through a through hole (not shown) provided in the center of the rear surface of the rear case 41, and heat is radiated into the rear case 41. A sheet 107 is attached.

  Next, as shown in FIG. 3, the screw groove 51 a of the lid 51 of the wire harness 49 is screwed into the screw groove formed in the through hole, and the through hole is closed by the lid 51.

  Then, the circuit board 72 on which the imaging element 30 is mounted and the lens holder 36 in which the imaging lens 29 is built are arranged in front of the rear case 41, and the connector 49b of the wire harness 49 is connected to the circuit board 72, A heat dissipation sheet 107 is attached to a part of the rear surface of the circuit board 72. Then, the screw 46 is passed through the screw through hole 75 of the lens holder 36, and the screw 46 is screwed into the screw hole 56 of the rear case 41, thereby fixing the lens holder 36 together with the circuit board 72 to the rear case 41. . Thereby, the imaging device 30 and the imaging lens 29 are fixed to the rear case 41.

  Subsequently, as shown in FIG. 4, both prisms 24 a and 24 b are fixed to the lens holder 36 by the prism fixing member 77. Specifically, the prisms 24a and 24b are arranged so that the prism rear surfaces 67a and 67b come into surface contact with the tapered surfaces of the contact bases 89L and 89R formed on the upper and lower ends of the base 83, respectively. Then, the holding body 85 is mounted from the front of both prisms 24a and 24b.

  At this time, the rear end portion of the central piece 105 is inserted into the groove 91 of the pedestal 83 while the prism side surfaces 69L and 69R of the prisms 24a and 24b are brought into contact with the left and right side surfaces of the central piece 105.

  In this state, the screw 79 is passed through the screw through-hole 103 of the base 99 of the holding body 85, the tip of the screw 79 is screwed into the screw hole 81 of the lens holder 36, and the prism fixing member 77 is fixed to the lens holder 36. To do. At this time, the elastic contact portions 82 at the rear end portions on both sides of the pedestal 83 contact the lens holder 36. Then, the pedestal 83 is pressed rearward at the rear ends of the prisms 24a and 24b pressed backward by the front end plate 93 of the holding body 85, and the elastic contact portions 82 at the rear end portions on both sides of the pedestal 83 serve as lens holders. It is pressed to the 36 side. As a result, in the rear case 41, the prism rear surfaces 67a and 67b are positioned by the tapered surfaces of the contact base portions 89L and 89R of the pedestal 83, as shown in FIG. The upper and lower ends of 24a and 24b are positioned by the upper and lower plates 97 of the holding body 85, the front ends of both prisms 24a and 24b are positioned by the front end plate 93 of the holding body 85, and the side ends of both prisms 24a and 24b. Is positioned by the side end plate 95 of the holding body 85, the positions of the prisms 24 a and 24 b are determined in the prism fixing member 77. That is, the prisms 24a and 24b are positioned with respect to the rear case 41.

  After that, as shown in FIG. 5, a frame-like seal member (packing) 61 is sandwiched so that the front case 43 is covered from the front of the rear case 41, and the screw 45 is passed through the screw through hole 55 of the rear case 41 from the rear. Then, the tip of the screw 45 is screwed into a screw hole (not shown) of the front case 43, and the in-vehicle imaging device shown in FIG. 1 is completed.

  In this way, the prisms 24a and 24b can be accurately positioned with respect to the transparent window portions 21L and 21R of the front case 43. That is, the prism side surfaces 65L and 65R of both the prisms 24a and 24b can be accurately set parallel to the inner surfaces of the transparent window portions 21L and 21R as shown in FIG.

<Operation>
The operation of the in-vehicle imaging device having the above configuration will be described. As shown in FIG. 6, the light beam corresponding to the right-side view enters from the transparent window 21R, passes through the prism side surface 65R, is internally reflected by the prism side surface 69L and the prism side surface 65R, and then exits the prism rear surface 67b to form an image. It is guided through the lens 29 to the right half of the imaging surface of an imaging device (not shown). The light beam corresponding to the left scene is also guided to the left side of the imaging surface in the same manner from the left-right symmetry. In this way, the left and right landscapes are simultaneously imaged by the in-vehicle imaging device, and such video is output to the display unit through the wire harness 49.

  Here, as shown in FIG. 7, for example, the light beam 110 taken in from the transparent window portion 21R of the case 23 is divided into one 111 incident on the prism side surface 65R and one reflected on the prism side surface 65R.

  In this case, if the inner surface 6 of the transparent window portion 21R and the prism side surface 65R are non-parallel, the light 3b reflected by the prism side surface 5 is reflected on the inner surface of the transparent window portion 1 as in the conventional example shown in FIG. 6 and is incident on the prism side surface 5 again, and the incident light 3b is displayed on the screen as stray light. Of course, the same applies to light rays taken in from the left side.

  However, in this embodiment, as described above, the prism side surfaces 65L and 65R of both the prisms 24a and 24b are made transparent with respect to the inner surfaces of the transparent windows 21L and 21R by the prism fixing member 77 as shown in FIG. Since it can be accurately set parallel to the windows 21L and 21R, the light 113 (FIG. 7) reflected by the prism side surfaces 65L and 65R is further reflected by the inner surfaces of the transparent windows 21L and 21R and again. When the light enters the prism side surfaces 65L and 65R, the light enters the same light path as that of the original light 113 or a parallel light path. Therefore, the generation of stray light can be greatly reduced as compared with the conventional example shown in FIG.

  In particular, when imaging with a single imaging device using a pair of prisms 24a and 24b, positioning of both prisms 24a and 24b is more difficult than with a single prism, but both prisms can be easily fixed with a prism fixing member 77. It is possible to perform positioning of 24a and 24b.

1 is an external perspective view showing an in-vehicle imaging device according to an embodiment of the present invention. It is a perspective view which shows the state in the middle of the assembly of the vehicle-mounted imaging device which concerns on one embodiment of this invention. It is a perspective view which shows the state in the middle of the assembly of the vehicle-mounted imaging device which concerns on one embodiment of this invention. It is a perspective view which shows the state in the middle of the assembly of the vehicle-mounted imaging device which concerns on one embodiment of this invention. It is a perspective view which shows the state in the middle of the assembly of the vehicle-mounted imaging device which concerns on one embodiment of this invention. It is a schematic diagram which shows a part of vehicle-mounted imaging device which concerns on one embodiment of this invention. It is a schematic diagram which shows the principle by which generation | occurrence | production of a stray light is reduced in the vehicle-mounted imaging device which concerns on one embodiment of this invention. It is a schematic diagram which shows the principle which a stray light generate | occur | produces in the conventional vehicle-mounted imaging device.

Explanation of symbols

21L, 21R Transparent window portion 23 Case 24a, 24b Prism 29 Imaging lens 36 Lens holder 41 Rear case 43 Front case 45 Screw 46 Screw 47 Radiation fin 49 Wire harness 55 Screw through hole 56 Screw hole 57 Light transmission hole 65L, 65R Prism Side surface 67a, 67b Prism rear surface 69L, 69R Prism side surface 71 Protective film 72 Circuit board 75 Screw through hole 77 Prism fixing member 79 Screw 81 Screw hole 83 Base 85 Holding body 87 Frame body 89L, 89R Abutment portion 91 Groove 93 Front end plate 95 side end plate 97 top and bottom plate 99 base 101 window frame 103 screw through hole 105 central piece 107 heat dissipation sheet

Claims (4)

A case with transparent windows on both left and right sides;
An image sensor disposed behind the case;
An optical system that is housed in the case and collects light to the image sensor;
A prism that reflects the light received through the transparent window portion from the left and right sides stored in the case to the optical system side;
An in-vehicle imaging device comprising: a prism fixing member that holds a prism side surface facing each transparent window portion of the prism in parallel with an inner surface of the transparent window portion. The in-vehicle imaging device according to claim 1,
An in-vehicle imaging device, wherein the prisms are mounted in a pair on the left and right. The in-vehicle imaging device according to claim 1 or 2,
The prism fixing member is
A pedestal that contacts the end of the rear surface of the prism;
An in-vehicle imaging device comprising: a holding body that holds the prism in contact with the front end portion of the prism while determining an angular position by being faced to the upper and lower end portions and side end portions of the prism. The in-vehicle imaging device according to claim 3,
An optical system holding member for holding the optical system;
First fixing means for fixing the optical system holding member to the case;
A vehicle-mounted imaging device further comprising second fixing means for fixing the holding body to the optical system holding member.

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