Abstract:
A sensor device is provided for generating an electrical output signal in dependence on the position of a light source in relation to the sensor device. The sensor device has a three-dimensional switch carrier with several adjacent faces oriented in different directions, on which faces at least two sensors are arranged. On the two sides of a central face, there is arranged in each case a face, with an infrared light (IR) photodetector in each case, oriented at an angle to the central face, whereby the faces on which the IR photodetectors are arranged are not directly adjacent to one another.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     Applicants claim priority under 35 U.S.C. §119 of German Patent Application No. 103 40 346.9 filed Aug. 29, 2003.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a sensor device for generating an electrical output signal in dependence on the position of a light source in relation to the sensor device.  
         [0004]     2. The Prior Art  
         [0005]     A sensor device of the type mentioned at the outset is known from EP 0 350 866 B1. The known sensor device has a photodetector, to which a geometrically specially formed light modulator is assigned. A light diffuser for the diffuse propagation or the dispersion of the incident light is also arranged between the light modulator and the photodetector.  
       SUMMARY OF THE INVENTION  
       [0006]     The problem underlying the invention is to provide a sensor device of the type mentioned at the outset, which is constructed in a particularly simple and space-saving manner.  
         [0007]     The solution to this problem takes place with a sensor device in accordance with the invention as described below. Advantageous developments of the invention are also discussed below.  
         [0008]     With a sensor device for generating an electrical output signal in dependence on the position of a light source in relation to the sensor device, whereby the sensor device has a three-dimensional switch carrier with several adjacent faces oriented in different directions, on which faces at least two sensors are arranged, it is essential to the invention that, on the two sides of a central face oriented in particular forwards, there is arranged in each case a face, with an infrared light (IR) photodetector in each case, oriented at an angle to the central face, whereby the faces on which the IR photodetectors are arranged are not directly adjacent to one another. A photodetector which is designed as a photodetector in the region of visible light is preferably arranged on the central face.  
         [0009]     Such a sensor device is used in particular in motor vehicles in order to generate a signal in dependence on the radiation intensity and radiation direction and in order to be able to ascertain the incident light radiation, in particular the direction of the insolation, and then, in the dependence thereon, suitably to control certain systems, for example an air-conditioning system. As a result of the sensor device according to the invention, two or more sensors that reliably detect, in particular, the lateral irradiation can be arranged on a small space. Specially designed light guides are not absolutely essential with such a form of embodiment. In addition, such a sensor device can be produced particularly small. The sensors of the sensor device can for example be designed as temperature sensors or preferably as photodetectors. In particular, the control of an air-conditioning system in motor vehicles is possible with such sensors.  
         [0010]     A photodetector for detecting visible light is arranged to advantage on the central face preferably oriented forwards in the travel direction of the motor vehicle. This face and therefore the photodetector arranged thereon are arranged tilted somewhat to the rear.  
         [0011]     The sensor device preferably has three sensors, in particular three photodetectors, which are arranged in different orientations from one another. At least two photodetectors are preferably designed as IR photodetectors. Such IR photodetectors measure particularly well the thermal irradiation from the sun. These two photodetectors are preferably, oriented towards the sides of the motor vehicle, so that it can be established whether the insolation is coming more from the right-hand side of the vehicle or more from the left-hand side of the vehicle and an air-conditioning system can be controlled accordingly. In a preferred development of the invention, one of the photodetectors is designed as a photodetector in the region of visible light. Such a photodetector is used in particular for the simulation or detection of the light that the human eye also perceives and is therefore particularly suitable for generating signals that are decisive for switching-on or switching-off the interior instrument lighting and/or the driving lights or dipped beams. The photodetectors are preferably designed as photodiodes.  
         [0012]     In a particularly preferred development of the invention, the photodetectors are fixed on a three-dimensional, injection-molded switch carrier. In particular, an MID technique (Molded Interconnect Devices) is used, whereby such an MID element consists of a three-dimensional conductor, in particular a thermoplastic with conductor strips arranged thereon, whereby the described photodetectors or photodiodes, in particular, are arranged on these conductor strips. The sensor device is preferably designed in such a way that the surface normals of the sensors, in particular of the IR photodetectors, intersect at an angle between 90° and 180°, in particular at an angle between 100° and 120°. In another, particularly preferred development, the surface normals of the IR photodetectors intersect at an angle between 60° and 80°, in particular at an angle of 70°. The surface normals of the IR photodetectors have intersecting angles with the base plane of the sensor device that diverge from 90° in both dimensions. The angle between the surface normals of the IR photodetectors and the base plane preferably lies between 35° and 55°, in particular at 45°. This means in particular that the IR photodetectors are not only arranged on faces inclined to the sides, but also that these faces are also tilted or tipped. In the travel direction relative to the car, the sensor device is used in such a way that the faces are tilted obliquely forwards. The IR detectors are preferably arranged symmetrical to the centrally arranged photodetector for visible light.  
         [0013]     In a further development of the invention, a display for a theft warning system is integrated into the sensor device. This display is preferably aligned parallel to a base plane of the photodetector device. This display is thus oriented upwards and readily visible.  
         [0014]     In another preferred development, the sensor device has a light-transmitting cover covering the photodetectors. The cover is preferably made from a light-transmitting plastic and can, according to the desired light characteristic, be colorless, whitish, greenish or greyish. In a particularly preferred development of the invention, the cover has additional optical elements. With such optical elements, the directional sensitivity already produced by the geometrical orientation of the IR photodetectors can be enhanced. The optical elements are preferably designed as light-conducting elements, in particular tubular ones, directed onto the sensors, especially the IR photodetectors. The light-conducting elements are preferably oriented at right angles to the photodetectors. In this way, a particularly reliable direction-dependent evaluation is possible. The light-conducting elements can preferably also be designed as lenses and/or as specially formed wall sections. The specially formed wall sections can be formed as a special light-conducting element by fluting, a special roughness or by another, in particular thinner, wall thickness. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]     Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawings. It should be understood, however, that the drawings are designed for the purpose of illustration only and not as a definition of the limits of the invention.  
         [0016]     In the drawings, wherein similar reference characters denote similar elements throughout the several views:  
         [0017]      FIG. 1  is a perspective overall view of a sensor device according to the invention;  
         [0018]      FIG. 2  is a second perspective view of a sensor device according to the invention, in which a part of the cover covering the sensor device is shown cut away;  
         [0019]      FIG. 3  is a perspective view of a three-dimensional switch carrier of the device according to the invention;  
         [0020]      FIG. 4  is a bottom view of the injection-molded switch carrier according  FIG. 3 ;  
         [0021]      FIG. 5  is a perspective view of a lower housing of the sensor device;  
         [0022]      FIG. 6  is a perspective view of the cover of the sensor device according to the invention from below;  
         [0023]      FIG. 7  is a perspective view of a second form of embodiment of a three-dimensional switch carrier of the device according to the invention;  
         [0024]      FIG. 8  is another perspective view of the second switch carrier according to the invention, according to  FIG. 7 ; and  
         [0025]      FIG. 9  is a third perspective view of the second switch carrier according to the invention, according to  FIG. 7 .  
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0026]     Perspective views of sensor device  1  according to the invention are represented in  FIGS. 1 and 2 . The sensor device essentially comprises-three elements, i.e. a three-dimensional, injection-molded switch carrier  3 , a lower housing  5  and a cover  6 . Injection-molded switch carrier  3  is accommodated in a box-like basic body  50  of lower housing  5 , which in turn has spring legs  51  with which the injection-molded switch carrier can be arranged, for example, on a dashboard of a motor vehicle. Lower housing  5  is also provided with snap-in elements, which co-operate with corresponding snap-in elements in cover  6 .  FIG. 1  shows a cover  6  which is formed from a homogeneous layer, which purely and simply has a protecting and light-scattering function, so that the light entering through cover  6  reliably falls onto photodetectors  31 ,  32  and  33  lying thereunder and, in addition, display  34  of the theft warning system can be seen from the exterior. The individual elements of sensor device  1  will be explained further in the following by reference to the individual representations in FIGS.  3  to  6 .  
         [0027]      FIG. 3  shows a first perspective view, i.e. essentially a view from above, onto injection-molded switch carrier  3  with IR photodetectors  31  and  32  arranged thereon and photodetector  33  for visible light. The three photodetectors are designed as photodiodes, which are arranged on the injection-molded three-dimensional switch carrier. Each photodetector is arranged on a plane of injection-molded switch carrier  3 .  
         [0028]     Injection-molded switch carrier  3  has in total four faces occupied by functional units, all of said faces being oriented at different angles to one another. An upper plane, for accommodating display  34  of the theft warning system, is provided parallel to base plane  39  of injection-molded switch carrier  3  and also sensor device  1 . Display  34  for the theft warning system is oriented precisely upwards. This plane is designed trapezoidal, and joining onto the oblique sides are two planes sloping forwards, on which IR photodiodes  31  and  32  are arranged. IR photodiodes  31  and  32  are facing the outsides, viewed in the travel direction of the car, and are oriented forwards, running inwards and at the same time tilted upwards. on the short parallel side of the trapezium, on which display  34  of the theft warning system is arranged, there is arranged an essentially square face oriented essentially forwards and slightly upwards, with photodetector  33  for visible light. This photodetector  33  is used for the control of the instrument lighting. Joining onto the two sides of the face with photodetector  33  there are in turn the faces with IR photodetectors  31  and  32  running at an angle with respect to this face.  
         [0029]      FIG. 4  shows a bottom view of injection-molded switch carrier  3 , whereby base plane  39  with electrical and/or electronic components  36  arranged thereon is shown in particular. Faces  30  of injection-molded switch carrier  3  are essentially produced from a thermoplastic material, whereby the electrical connections for the photodetectors and electronic components  36  are provided thereon. Four connection pins  37  for activating the photodetectors and display  34  are also provided.  
         [0030]      FIG. 5  shows lower housing  5 , which essentially has a box-shaped basic body  50 , on which springs  51  pointing downwards are arranged, with which the sensor device is fixed at the assembly point. Injection-molded switch carrier  3  with its base plane  39  can be inserted in a keyed manner into box-shaped basic body  50 . Snap-in elements  53  are also provided in the outer area and snap-in elements  54  on the top side.  
         [0031]      FIG. 6  shows a bottom view of cover  6 , which is essentially made from a transparent or semi-transparent plastic material  60 . Integrated into this cover  6 , which as a rule is also injection-molded, are snap-in elements  63  and  64 , which correspond to snap-in elements  53  and  54  of lower housing  5 . As additional to the representation of cover  6  in  FIGS. 1 and 2 , there are provided here light-conducting elements  61 ,  62 , which are designed tubular and enable an amplified, direction-dependent incident light radiation onto IR-photodetectors  31  and  32  arranged below them.  
         [0032]      FIG. 7  shows a perspective view of a second form of embodiment of a switch carrier according to the invention, comparable to  FIG. 3 . Switch carrier  3  also has IR-photodetectors  31  and  32  and photodetector  33  for visible light. The switch carrier is used in a motor vehicle in such a way that photodetector  33  is oriented forwards. Base plate  39  is mounted horizontally, so that photodetector  33  is tilted with its plane sloping backwards over lower face  44 , so that photodetector  33  is tilted slightly upwards. Faces  30  with IR-photodetectors  31  and  32  mounted thereon follow on at the right-hand and left-hand side of photodetector  33 . In relation to the face of photodetector  33 , the IR photodetectors  31  and  32  are tilted sloping backwards and upwards. A particularly good direction-dependent detection of the insolation thus becomes possible. A particularly precise directional characteristic results. Flexible possibilities for the design of the directional characteristic also result from the overall design of three-dimensional switch carrier  3 . A number of photodiodes can also be accommodated on the basic body, so that the variability of the possibilities is increased still further. This form of embodiment of the switch carrier can also be used in combination with a certain filter characteristic of the cover and optionally of the photodetector, as a result of which a wave-dependent detection and evaluation of the sunlight becomes possible.  
         [0033]     Underneath face  30  with a IR-photodetector  31  is a face  41 , which is tilted with respect to face  30 . Face  41  extends to base plane  39  and ends on base plane  39 , whereby a free corner of base plane  39  remains. Face  41  abuts the front central face, on which the photodetector  33  is provided, and has a common line with face  44 . Face  42  is disposed adjacent face  41 , opposite to the side of face  41  having the common lines with a central face and face  44 . Face  42  is tilted with respect to face  41  and extends mainly perpendicular from the base plane  39  upwards. Face  42  abuts face  30  in a corner area. At the top of face  42  is arranged a tilted face  43 , which abuts tilted face  30  and on the tilted horizontal upper face, on which a display  34  is positioned.  
         [0034]      FIG. 8  is a further perspective view of switch carrier  3 , whereby switch carrier  3  is shown essentially from below, i.e. from the side of base plane  39 . Surface normals through the faces of IR photodetectors  31  and  32  are represented as lines. These lines intersect at an angle of 70°. The photodetectors are oriented to one another at an angle of 70° ±10°, since a particularly good examination of the irradiation characteristic of the sun is thus achieved even with a relatively low solar attitude.  
         [0035]      FIG. 9  shows the three-dimensional switch carrier in a view such that the face of IR photodetector  31  stands perpendicular in the plane of the drawing, so that the surface normal to IR photodetector  31  is shown by the dashed line. The surface normal of IR photodetector  31  is at an angle of 45° to the vertical or perpendicular of overall switch carrier  3 . In alternative embodiments, this angle amounts to ±10°. On account of the mirror-symmetrical structure of switch carrier  3 , the face of IR photodetector  32  is similarly at an angle of 45° to the vertical or also to base plane  39 .  
         [0036]     Although only a few embodiments of the present invention have been shown and described, it is to be understood that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention as defined in the appended claims.