Abstract:
In a camera system to be installed in a passenger compartment of motor vehicle, a camera ( 3 ) is surrounded by a housing ( 7 ) and is oriented towards the windshield ( 1 ) of the passenger compartment. Between the camera ( 3 ) and the windshield ( 1 ) a shield ( 11 ) is provided, which is moveable between a closed position in which the camera ( 3 ) is shielded against scatter light from the passenger compartment and an open position in which access may be had to the front lens ( 4 ) of the camera ( 3 ) and the area ( 6 ) of the windshield lying in the field of view of the camera ( 3 ).

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of Invention  
         [0002]     The present invention concerns a camera system to be mounted in the passenger compartment of motor vehicle. This type of camera system has been proposed in recent years in order, for example, to continuously monitor the environment of the vehicle while driving, and to record images taken at this time in a recording media, which media written over after a short storage interval, so that after the vehicle is involved in an accident images of the environment are available covering the last seconds prior to the accident, which images can be used in order to clear up, for example, the cause of the accident and to assign responsibility. Another application of this type of camera system is in systems for automatic assistance of the driver, who on the basis of images supplied by such a camera system is able, for example, to judge the distance to a preceding vehicle and to more rapidly adapt the own speed of the vehicle and the spacing than the driver could do alone, or which system is able to recognize those exceptional situations, such as for example the departure of the vehicle from the lane during a momentary falling sleep of the driver, and to produce a warning signal in order to wake the driver.  
         [0003]     2. Related Art of the Invention  
         [0004]     It is important for the effectiveness of such a camera system that the camera has an unobstructed field of view. In order to prevent obstruction of the camera by dirt on the windshield behind which the camera is located, it is proposed in DE 43 29 983 A1 to place the camera in an area of the windshield of the vehicle which is cleaned by windshield wipers. An obstruction of the field of view of the camera by a fogging from inside can, however, not be prevented in accordance with the technique disclosed in this document.  
         [0005]     U.S. Pat. No. 5,096,287A1 teaches a camera system in a motor vehicle, the camera mounted on the arm which carries a rear view mirror. The camera is directed forwardly to take pictures through the front windshield of the motor vehicle and a backlight shield or boot is provided between the camera and the windshield, with the front edge of the shield flush against the inside of the windshield. In order to prevent fogging of the windshield in the field of view of the camera, a forced air ventilation channel passes through the camera bracket, through which air flows into the space between the camera, backlight shield and windshield, which air subsequently flows out of ventilation holes in the backlight shield. This solution is undesirably complex to implement, since the introduction of forced air occurs through conduits built into the roof of the vehicle. Further, it does not provide immediate relief when the windshield is fogged in the field of view of the camera. Further yet, it is not possible for the driver to determine whether the field of view of the camera is clear, since the backlight shield conceals the field of view of the camera in the vicinity of the windshield from the view of the driver.  
       SUMMARY OF THE INVENTION  
       [0006]     It is the task of the present invention to provide a camera system for installing in the passenger compartment of a motor vehicle, wherein on the one hand the camera is protected from interfering reflections from the passenger compartment, while on the other hand it should be possible for the driver to easily check that the field of view of the camera is free of impediments and, if present, for him to remove these.  
         [0007]     This task is solved by a camera system with the characterizing features of claim  1 . The moveability of the shield makes it possible for the driver to expose, at any time, the area of the windshield through which the camera views towards the outside in order to check whether the field of view of the camera is unimpeded and, when necessary, to remove precipitation from this area of the windshield or from the front lens of the camera. When the shield, following such an operation, is returned to its closed condition, then the camera can operate without interference from reflections from the passenger compartment.  
         [0008]     In a first embodiment of the invention the shield is pivotable between its two positions. This shield is preferably coupled to the camera housing, which for its part is rigidly mounted. It is however also conceivable that the shield is pivotable back and forth together with the camera housing as a integral unit.  
         [0009]     Since the camera is a safety related device for the vehicle, and as such must possess a high degree of reliability, it is considered advisable to employ as the linkage mechanism for the shield a friction hinge, which imparts to the driver an impression of high value workmanship consistent with the quality necessary of the camera.  
         [0010]     In a second embodiment the shield is slideable between two positions, and for simplicity it is preferred that the shield and the housing are slideable as a unit.  
         [0011]     An air channel is preferably formed between the housing and the camera, through which air can flow, which entrains the exhaust heat from the camera and thereby cools the camera.  
         [0012]     In order to emit the warmed air and/or to allow the inflow of fresh air, the housing is preferably provided with a ventilation opening. Likewise, for ventilation, a gap is preferably formed between the windshield and one of the edges of the shield facing the windshield.  
         [0013]     It is frequently the case that the edge area of the windshield of a motor vehicle is provided with a light-impermeable coating, in order to conceal underlying areas, for example, the adhesives or molding of the windshield. A light impermeable area in a windshield can be used to advantage, by leaving a transparent window open, through which the camera can view and which in the closed or engaged position of the shield is covered over thereby. When the edge of the window is completely covered by the shield, then any tolerances or imperfections during installation of the camera are well hidden. When the light impermeable area is black, then it simultaneously works as a stray light shield for the camera. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     Further features and advantages of the invention can be seen from the following description of illustrative examples with reference to the attached figures. There is shown:  
         [0015]      FIG. 1 a  schematic section through an inventive camera system according to a first embodiment, with closed shield;  
         [0016]      FIG. 2  the camera system according to  FIG. 1 , with open shield;  
         [0017]      FIG. 3 a  second embodiment of the inventive camera system with a section analogous to  FIGS. 1 and 2 ;  
         [0018]      FIG. 4 a  third embodiment of the inventive camera system with a section analogous to  FIGS. 1 and 2 ;  
         [0019]      FIG. 5 a  section through the camera system of  FIG. 4  along line V-V of  FIG. 4 ;  
         [0020]      FIG. 6 a  fourth embodiment of the inventive camera system with a section analogous to  FIGS. 1 and 2 ; and  
         [0021]      FIG. 7 a  section through the camera system of  FIG. 6  along line VII-VII of  FIG. 6 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0022]      FIG. 1  shows a schematic section through a camera system according to a first embodiment of the invention. A mounting bracket  2  is adhered to a windshield  1  of a motor vehicle, to which in turn an electronic camera  3  is secured. The camera  3 , since it is so well known, is shown essentially schematically by its outline; basically it&#39;s front lens  4  is shown. The windshield  1  is, for its part, provided on its inner side with a black coating, which hides the camera system from the outside; essentially only a transparent window  6  is left free, through which the camera  3  can see the outside.  
         [0023]     Towards the passenger compartment the camera  3  is covered by a shell-like housing  7 , in the lower area of which a plurality of holes  8  are formed, which permit the inflow of fresh area into the inside of the housing  7  below the camera  3 . The mounting bracket  2  is broader than the camera  3  itself in the direction transverse to the section plane of  FIG. 1 , and includes engagement means on (not shown) side flanks, which cooperate with complementary engagement means of the housing  7 , in order to hold the housing  7 . The camera  3  itself does not contact the housing  7 , such that along its backside and on both side-flanks channels  9  extend between the camera  3  and the housing  7 , through which air entering the housing  7  through the holes  8  flows along the camera  3 , warms itself, and finally exits from the gap  10 , through which the housing  7  is separated from the windshield  1 .  
         [0024]     In a front lower area of the housing  7  a shield  11  is linked to the housing  7  via a hinge  12 . The shield  11  appears, viewed from outside, to be a flush continuation of the housing  7 . It is provided, on the windshield  1  facing edge, with an approximately finger-wide and finger-deep cutout  13 , which makes it possible for the driver to grasp behind the shield and to flip it open when the driver would like to check whether the window  6  is clear or whether condensation must be wiped from the windshield  1 . The hinge  12  is friction limited, in particular, it exhibits friction to the extent that on the one hand the folding open is not made difficult thereby, however, it remains fixed in any position in which it is released, even at positions between the closed position shown in  FIG. 1  and the open position shown in  FIG. 2 .  
         [0025]     In order not to have to make the friction of the hinge  12  too strong, and yet to reliably prevent an opening of the shield  11  even during bumpy driving, a magnetic closure means can be provided, which supports shield  11 , keeping it in its closed position.  
         [0026]     In the embodiment according to  FIG. 3  the housing  7 ′ and the shield  11 ′ are fused into a single piece, that is, the shield  11 ′ is a single piece of the housing  7 ′ projecting in front of the housing  7 ′ beyond the front lens  4  or the body of the camera  3 , covering over the viewing window  6  of the camera, and the housing  7 ′ as a single piece is hinged to the mounting bracket  2  via a hinge  14  in the upper rear edge area. Thus the housing  7 ′ is pivotable out of its closed position shown with a solid line into an open position as shown, for example, in dashed lines in  FIG. 3 , in which open position not only the window  6  but also the camera  3  is exposed.  
         [0027]      FIG. 4  shows a third embodiment of the inventive camera system in a section analogous to  FIGS. 1-3 , wherein the housing  7 ″, which again together with the shield  11 ″ is fused into a single piece, is slideable on tracks between a closed position shown with continuous lines and an open position shown with dashed lines. These tracks are formed by two bracket arms  16  which, beginning from the mounting bracket  2 , engage about two sides of the camera  3  and respectively have an outwardly oriented spring  17 . The two springs  17  are, as can be seen in the horizontal section of  FIG. 5 , guided in the horizontal groove  18 , which are respectively formed by two ribs  19 ,  20  projecting from the side flanks of the housing  7 ′. The two grooves  18  are respectively terminated by an abutment projection  21  at the front edge of the housing  7 ″ facing towards the windshield  1  which in the open position shown with solid lines in  FIG. 5  respectively abut against one edge of the springs  17  and thus prevent a complete pulling off the housing from the mounting bracket  2 . During mounting of the housing  7 ″ to the mounting bracket  2  the side flanks  22  of the housing are spread apart for a short period, such that the engagement projections  21  can pass the springs  17 . In appropriate manner the housing  7 ″ can also be dismounted, in order to have access to the camera  3  as necessary. Under normal conditions the housing  7 ″ when in the open position however allows access only to the window  6  and the front lens  4 .  
         [0028]     Here also, as can be clearly seen in the section according to  FIG. 5 , the camera  3  is surrounded on three sides by flow channels  9 , in which air entering through the holes  8  at the lower side of the housing  7 ′ can flow along the camera  3  and finally can escape through the gap  10  between the housing  71  and windshield  1 .  
         [0029]      FIGS. 6 and 7  show a fourth embodiment of the invention in two sections analogous to those of  FIGS. 4 and 5 . Housing  7 ″′ and shield  11 ″′ are here, again, formed as two parts, and this namely in the manner that the plate shaped shield  11 ″′ is guided in grooves  23  of a section  24  of the housing slidable between a (not shown) closed position, in which it is flush with and closes the cutout  24 , and an open position shown in the Figs., in which it permits access to the window  6  and the front lens of the camera  3 .