Sensor arrangement and method for operating a sensor arrangement

Abstract

A sensor arrangement comprises at least a first, a second, and a third light sensor. A three-dimensional framework comprises at least a first, a second, and a third connection means which are connected to the at least first, second, and third light sensor, respectively. The first, the second, and the third connection means are configured to align the at least first, second, and third light sensor along a first, second, and third face of a polyhedron-like volume, respectively, such that the sensor arrangement encloses the polyhedron-like volume. The invention also relates to a method for operating the sensor arrangement.

We claim: 
     
         1 . A sensor arrangement comprising:
 at least a first, a second, and a third light sensor,   a three-dimensional framework comprising at least a first, a second, and a third connection means connected to the at least first, second, and third light sensor, respectively, and   the first, the second, and the third connection means being configured to align the at least first, second, and third light sensor along a first, second, and third face of a polyhedron-like volume, respectively, such that the sensor arrangement encloses the polyhedron-like volume.   
     
     
         2 . The sensor arrangement according to  claim 1 , wherein the first, the second, and the third light sensor are
 aligned with their light-sensitive surfaces facing away from the polyhedron-like volume, and are   configured to detect light from within a continuous region of interest depending on the polyhedron-like volume.   
     
     
         3 . The sensor arrangement according to  claim 1 , wherein the at least first, second, and third light sensor
 are aligned with respect to a three-dimensional coordinate system, and   have a sensor response characteristic proportional to a direction cosine in the three-dimensional coordinate system.   
     
     
         4 . The sensor arrangement according to  claim 1 , wherein the at least first, second, and third light sensors comprise a photo-diode, a CMOS light detector, and/or a CCD, respectively. 
     
     
         5 . The sensor arrangement according to  claim 1 , wherein the at least first, second, and third light sensors comprise a color sensor, respectively. 
     
     
         6 . The sensor arrangement according to  claim 1 , wherein
 the three-dimensional framework comprises the polyhedron-like volume, in particular, comprises a solid body having the polyhedron-like volume,   the first, second, and third connection means constitute the first, second, and third face of the polyhedron-like volume, and   the connection means are configured to provide electrical terminals to the at least first, second, and third light sensor.   
     
     
         7 . The sensor arrangement according to  claim 1 , wherein the three-dimensional framework comprises a grid having an envelope comprising the polyhedron-like volume. 
     
     
         8 . The sensor arrangement according to  claim 1 , wherein
 the polyhedron-like volume comprises a four-faceted pyramid or a frustum thereof, in particular a pyramid with a square base or a frustum thereof,   the first, second, and third light sensors are aligned along the first, second, and third face of the four-faceted pyramid or the frustum thereof, and   a fourth light sensor is aligned to a fourth face of the four-faceted pyramid or the frustum thereof.   
     
     
         9 . The sensor arrangement according to  claim 1 , wherein
 the polyhedron-like volume comprises a cube,   the first, second, and third light sensors are aligned along the first, second, and third face of the cube, and   the fourth light sensor is aligned along the fourth face of the cube.   
     
     
         10 . The sensor arrangement according to  claim 9 , wherein a fifth light sensor and/or a sixth light sensor is/are aligned along a fourth and/or a sixth face of the cube. 
     
     
         11 . A method for operating a sensor arrangement comprising at least a first, a second, and a third light sensor wherein each light sensor is aligned along a face of a polyhedron-like volume, respectively, so that the sensor arrangement encloses the polyhedron-like volume, the method comprising the steps of:
 collecting from the at least first, second, and third light sensor respective sensor signals depending on a light source to be detected,   determine from the collected sensor signals projections onto the principal axes of a three-dimensional coordinate system, and   determine from the determined projections a direction of the light source to be detected with respect to the three-dimensional coordinate system.   
     
     
         12 . The method according to  claim 11 , comprising the step of aligning the at least first, second, and third light sensors with respect to the principal axes of the three-dimensional coordinate system, respectively. 
     
     
         13 . The method according to  claim 11 , wherein the step of aligning the at least first, second, and third light sensors further involves defining a continuous region of interest into which the light source to be detected emits a predetermined amount of light. 
     
     
         14 . The method according to  claim 11 , wherein from the sensor signals a relative brightness of the light source to be detected is determined by
 taking the square root of the sum of squared sensor signals, or by   taking the square root of the sum of squared difference signals, wherein the difference signals depend on the sensor signals.   
     
     
         15 . The method according to  claim 11 , wherein the steps of collecting sensor signals, determining the projections onto the principal axes and determining the direction of the light source to be detected is continuously repeated so as to track the direction of the light source within the three-dimensional coordinate system.