Abstract:
A device for attaching and contacting an electrical component, e.g., a sensor device, includes: at least two contact points which are electrically contactable via associated busbars, a contact point of the component being connected to the associated busbar via a respective connecting element, which at its respective free first end forms a mounting for the component and establishes the electrical connection to the contact point of the component in the mounting, and which at its respective second end is held on the busbar and is electrically connected thereto.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a device and a method for attaching and contacting an electrical component, in particular a sensor device, having at least two contact surfaces which are electrically contactable via associated busbars. 
         [0003]    2. Description of the Related Art 
         [0004]    It is known to use a circuit board for sensors which is equipped with a sensor element and, for example, with capacitors. The capacitors are used to increase the safety against electrostatic discharge (ESD safety). This equipped circuit board represents the electrical component or the sensor device which is usually electromechanically contacted in a plastic sensor housing with the aid of pressfit technology. Subsequently, the plastic sensor housing is tightly sealed with a plastic cover with the aid laser transmission welding (LTW). Alternative joining methods still require the complex soldering as an electromechanical joint and additionally apply a high mechanical load onto the circuit board or the electrical component. 
       BRIEF SUMMARY OF THE INVENTION 
       [0005]    The device and the method according to the present invention have the advantage over the related art that a simple device having little complexity for attaching and contacting the electrical component is provided, which requires fewer individual parts and fewer individual steps for manufacturing. 
         [0006]    In addition to a reduction of the manufacturing costs in mass manufacturing, it is furthermore also possible to achieve short tolerance chains. It is particularly advantageous that the use of smaller, thinner, and consequently also more sensitive components in the form of land grid arrays (LGAs) sheathed with the aid of injection molding processes is made possible. The method according to the present invention ensures that narrow position tolerances of the component in its mounting may even be adhered to at all times in mass manufacturing of the device. 
         [0007]    Good positioning and attachment of the LGA result when the mounting at the first end of the connecting element has a clamp-shaped and/or fork-shaped and/or bracket-shaped design. 
         [0008]    Reliable electrical contacting of the component with the connecting element results from a clamping contact within the mounting. 
         [0009]    Reliable shielding is accomplished by surrounding the component with a metal cage open at the end face, which is formed by mountings of the at least two connecting elements. 
         [0010]    Good positioning and attachment of the LGA results when the connecting element has a multi-piece design made up of multiple elements. 
         [0011]    A reliable electrical connection and shielding of the LGA and reliable attachment result when the connecting element is made of spring steel. 
         [0012]    A reliable electrical connection and attachment of the LGA result when the second end of the connecting element is connected to the busbar with the aid of clinching and/or with the aid of friction welding and/or with the aid of a clamping contact. 
         [0013]    A reliable electrical connection of the LGA results when the busbars include elevations for contacting the contact points of the component. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  shows in a perspective view a front view of a device according to the present invention for a two-pole component according to a first exemplary embodiment. 
           [0015]      FIG. 2  shows in a perspective view a corresponding rear view of the first exemplary embodiment. 
           [0016]      FIG. 3  shows in a perspective view a corresponding view from beneath of the first exemplary embodiment. 
           [0017]      FIG. 4  shows in a perspective view a front view of the device according to the present invention for a four-pole component according to a second exemplary embodiment. 
           [0018]      FIG. 5  shows in a perspective view a corresponding rear view of the second exemplary embodiment. 
           [0019]      FIG. 6  shows in a perspective view a corresponding view from beneath of the second exemplary embodiment. 
           [0020]      FIG. 7  shows in a perspective view a front view of the device according to the present invention for a two-pole component according to a third exemplary embodiment. 
           [0021]      FIG. 8  shows a corresponding top view onto the third exemplary embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]      FIG. 1  shows in a perspective front view a device  1  for attaching and contacting an electrical component  2 . Component  2  is a sensor device or an electronics module, as it is used in an acceleration sensor in the automobile sector, for example. The sensor device usually includes an acceleration chip, an application-specific integrated circuit (ASIC) chip, and passive components, which are all combined in a land grid array (LGA) sheathed with the aid of an injection molding process. The component or LGA  2  has a plate shape and, in the two-pole design, has at least two contact points  10 ,  11  on its top side  4  or on its bottom side  5 , which are indicated by dotted lines and are electrically contactable via busbars  15 ,  16 . Bottom side  5  of LGA  2  faces busbars  15 ,  16 ; top side  4  faces away from busbars  15 ,  16 . In the exemplary embodiment, contact points  10 ,  11  are provided on top side  4 . Busbars  15 ,  16  extending in parallel to each other are accommodated in an embedding  20 , for example made of plastic, a free section  21  of busbars  15 ,  16  projecting from embedding  20  from an end face  22 . Busbars  15 ,  16  are an integral part of a plug connection not shown in greater detail, for example of a plug which is used to contact component  2  or the acceleration sensor. 
         [0023]    According to the present invention, it is now provided that the attachment and electrical contacting of LGA  2  is carried out with the aid of connecting elements, a first connecting element  30  and a second connecting element  40 , which each connect one contact point  10 ,  11  of LGA  2  to associated busbar  15 ,  16 . As is shown in greater detail in  FIG. 2  in a perspective rear view of device  1 , each connecting element  30 ;  40  has a multi-piece design for this purpose and includes a contacting section  31 ;  41 , a connecting section  32 ;  42 , and a holding section  33 ;  43 . Contacting sections  31 ,  41  are oriented close to embedding  20  in the area of busbars  15 ,  16  and rest against provided widenings  23 ,  24  of busbars  15 ,  16 , for example. Contacting sections  31 ;  41  have a U-shaped cross section in order to encompass top side  17 ,  18  of busbars  15 ,  16  in a rail-like or clamp-like manner. Contacting sections  31 ,  41  each transition into the planar connecting section  32 ,  42  which extends on top side  17 ,  18  of busbars  15 ,  16  and on which the bracket-like, clamp-like holding section  33 ,  43  is formed. Holding sections  33 ,  43  together form the mounting of LGA  2  at a free first end  12  of connecting elements  30 ,  40 . Holding section  33  of first connecting element  30  extends upward from top side  17  of busbar  15  and encompasses a lateral surface  8  of LGA  2  in the manner of a clamp so that top side  4  and bottom side  5  of LGA  2  are partially accommodated in holding section  33 . Correspondingly, the opposing lateral surface  9  is encompassed by holding section  43  of second connecting element  40 . The two holding sections  33 ,  43  are positioned close to each other and completely cover lateral surfaces  8 ,  9  and substantially cover top side  4  and bottom side  5  of LGA  2 . Overall, holding sections  33 ,  43  thus form a mounting for LGA  2 , which remains open at its front side  6  and at its backside  7 , overall essentially a metal cage being present which surrounds LGA  2 . It is also conceivable to design holding sections  33 ,  43  in such a way that also backside  7  of LGA  2  is covered. As is shown in greater detail in a perspective view from beneath in  FIG. 3 , ends  19  of busbars  15 ,  16  terminate with front side  6  of LGA  2  and with holding sections  33 ,  43  of connecting elements  30 ,  40 . 
         [0024]    Corresponding insertion angles  25 ,  26  extend holding sections  33 ,  43  at the two lateral surfaces  8 ,  9  and on top side  4  of LGA  2  in order to simplify the insertion of LGA  2  in its mounting during assembly. Inserted LGA  2  is mounted by clamping, holding sections  33 ,  43  provided on top side  4  also performing the contacting of contact points  10 ,  11 . 
         [0025]    To avoid torque which could act on LGA  2 , the clamping contacting is carried out in such a way that the supporting surfaces, here top sides  17 ,  18  of busbars  15 ,  16 , are always positioned directly beneath the clamping contact point. This condition results in a metal cage having a multi-piece design. Connecting elements  30 ,  40  are preferably made of a resilient material, such as spring steel. LGA  2  has two contact points  10 ,  11  or has a two-pole design. A multi-pole design is also possible, as is shown in greater detail in  FIGS. 4, 5, and 6 . LGA  2  is composed as a system in package (SIP) and is electrically and mechanically contacted. This is also carried out in a multi-pole design. It is advantageous to enclose LGA  2  in holding sections configured as spring steel cage  33 ,  43 , preferably completely, in order to shield the same preferably well against electromagnetic radiation. The electrical contacting is carried out without a fused joint, such as soldering, but solely by the clamping contact within holding sections  33 ,  43  at contact points  10 ,  11 . The second end  14  of the spring steel cage or of connecting elements  30 ,  40  is, in turn, electromechanically connected to associated busbars  15 ,  16 . Busbars  15 ,  16  are made of bronze, for example. Busbars  15 ,  16  are an integral part of a plug for contacting LGA  2 . 
         [0026]    The joint between connecting elements  30 ,  40  made of spring steel and busbars  15 ,  16  made of bronze is a bond of dissimilar metals and is valued for its mechanical, electrical and chemical or corrosive properties. The electrical and chemical properties are primarily defined via the surfaces of the metal sheets which are used. These may be influenced via coatings or a layering system, as is known from plug connections. The mechanical stability must be designed in such a way that a durable joint is created which withstands the further processing and the loads in the application with sufficient reliability. 
         [0027]    The joint between spring steel elements  30 ,  40  and busbars  15 ,  16 , which are usually made of a bronze alloy, is preferably carried out by clinching at contacting sections  31 ,  41 . The contacting sections may have a circular opening  33 ,  34  toward busbars  15 ,  16 , for example. As an alternative, it is also possible to use friction welding or a clamping contact. Due to the increasing miniaturization of electronics components, the joint between dissimilar metals must be carried out in the smallest of spaces, which is why traditional connecting methods such as crimping or screwing are not an option. 
         [0028]      FIGS. 4 through 6  show a second exemplary embodiment in which all identical or like-acting components are denoted by the same reference numerals as the first exemplary embodiment. LGA  2  shown in a perspective top view in  FIG. 4  has a four-pole design and has four contact surfaces  10 ,  11 ,  100 ,  111 , which are provided in the area of the corners of LGA  2 , for example, and which are each contacted by a connecting element  30 ,  40 ,  50 ,  60 . Consequently four busbars  15 ,  16 ,  55 ,  65  are also present, two being provided in pairs on the outside, hereafter referred to as the first busbar  15  and the second busbar  16 , and two being provided in pairs on the inside. The inside busbars  55 ,  65  are hereafter referred to as the third busbar  55  and the fourth busbar  65 . The third busbar  55  and the fourth busbar  65  are located within a rectangular recess  222  of end face  22  in embedding  20  for busbars  55 ,  65 . Outside of recess  222 , the first and second busbars  15 ,  16  project from the planar end face  22  of embedding  20 . In this way, a lateral offset of the free ends  19  of paired busbars  15 ,  16  and  55 ,  65  exists, whereby a clearance  250  is present in between, which is used to accommodate LGA  2  within the mounting formed together by four connecting elements  30 ,  40 ,  50 ,  60  at their free first end  12 ,  122 . As is shown in greater detail in  FIG. 6  in a perspective view from beneath, front side  6  of LGA  2  protrudes beyond ends  19  of conductor rails  15 ,  16 , and its backside  7  terminates approximately with ends  19 . 
         [0029]    The composition of the four connecting elements essentially corresponds to that in the first exemplary embodiment. The first and second connecting elements  30 ,  40  connect the first and second busbars  15 ,  16  via their contacting sections  31 ,  41  with contact points  10 ,  11  on LGA  2 . Deviating from the first exemplary embodiment, contact points  10 ,  11  on top side  4  are provided closer to front side  6 . Moreover, connecting sections  32 ,  42  adjoining contact sections  31 ,  41  do not extend rectilinearly, but are angled, and cover the lateral surfaces  8 ,  9 , and it is not until the area of front side  6  or of contact points  15 ,  16  that they transition into holding sections  33 ,  43 , which therefore cover only a front portion on top side  4  of LGA  2 . Within holding sections  33 ,  43 , contact points  10 ,  11  are encompassed, which are designed in a clamp-like or bracket-like manner, as in the first exemplary embodiment. As is shown in greater detail in  FIG. 6 , holding sections  33 ,  43  are designed to be wider on bottom side  5 , where they cover approximately ⅔ of bottom side  5 . Moreover, the second holding section  43  of the second connecting element  40  is designed to be wider on bottom side  5  than the first holding section  33  of the first connecting element  30 . As in the first exemplary embodiment, insertion angles  25 ,  26  are provided at holding sections  33 ,  43  for improving assembly when inserting LGA  2  into the mountings. 
         [0030]    A third connecting element  50  and a fourth connecting element  60  connect the third busbar  55  and the fourth busbar  65  via their contacting sections  51 ,  61  with contact points  100 ,  111  on LGA  2 . Contact points  100 ,  111  are provided on top side  4  closer to backside  7 . Connecting sections  52 ,  62  extend rectilinearly and include their holding sections  53 ,  63  at their free end  122 . Holding sections  53 ,  63  are angled and essentially cramp-shaped or fork-shaped. Holding sections  53 ,  63  may then serve as a stop for LGA  2  during insertion of LGA  2  into holding sections  33 ,  43 . As in the first exemplary embodiment, all contacting sections  31 ,  41 ,  51 ,  61  have openings  34 ,  44 ,  54 ,  64  and are electrically and mechanically fixedly connected to busbars  15 ,  16 ,  55 ,  65  with the aid of clinching, for example. 
         [0031]    To ensure the position tolerance important for acceleration sensors, it is advantageous for manufacturing the device to initially connect the second ends  14 ,  144  of connecting elements  30 ,  40 ,  50 ,  60  to busbars  15 ,  16 ,  55 ,  65 , and to then insert component  2  into the shared mounting formed by the at least two connecting elements  30 ,  40 ;  50 ,  60 . This requires one open side in the spring steel cage, via which LGA  2  may subsequently be inserted. 
         [0032]      FIGS. 7 through 8  show a third exemplary embodiment in which identical or like-acting components are denoted by the same reference numerals as the preceding two exemplary embodiments. As is shown in a perspective view of device  1  in  FIG. 7 , busbars  15 ,  16  are modified compared to the two preceding exemplary embodiments by not being designed to be freely projecting, but accommodated in a protrusion or an overhang  70  spaced apart from end face  22  of embedding  20  for busbars  15 ,  16 , bottom sides  27 ,  28  of busbars  15 ,  16  being supported on overhang  70 . LGA  2  has a two-pole design, so that two busbars  15 ,  16  are present, which are accommodated in overhang  70  in embedding  20 . As is shown in greater detail in  FIG. 8  in a top view, contacting of LGA  2  on its bottom side  5  with contact points  10 ,  11  is carried out at the free top sides  17 ,  18  on provided elevations  151 ,  161  of busbars  15 ,  16 . Elevations  151 ,  161  of busbars  15 ,  16  are designed in the form of hemispherical bulges, for example. Contact points  10 ,  11  of LGA  2  are pressed against bulges  151 ,  161  with the aid of a clamp  80 , so that an electrical connection of LGA  2  with busbars  15 ,  16  is created by a clamping contact. Clamp  80  essentially encompasses top side  4  of LGA  2  and extends along top side  4  across lateral surfaces  8 ,  9  at a distance from the same and, with hook elements  81  on the bottom side, engages a bottom side  71  of overhang  70  for support. Clamp  80  forms a metal cage open at the end face. As in the preceding exemplary embodiments, clamp  80  is preferably made of spring steel and, contrary to the electrical and mechanical contacting of the preceding exemplary embodiments, assumes only the mechanical contacting of LGA  2  here. 
         [0033]    The device according to the present invention is provided for sensors, in particular for acceleration sensors in the automobile sector.