Abstract:
A forward looking light sensor is described herein. The sensor includes a first light blocking material; a second light blocking material; and a light sensor with a first surface and a second surface. The first light blocking material is disposed on the first surface of the light sensor and the second light blocking material is disposed on the first surface of the light sensor, and the first light blocking material and the second light blocking forming an aperture.

Description:
BACKGROUND 
       [0001]    A forward looking light sensor is customarily provided to detect a light or luminance that a viewer may see while looking outward or through a forward facing surface (e.g. a windshield). For example, if the viewer is looking outside of a window, a windshield, the forward looking light sensor may be employed to detect the light the viewer sees. 
         [0002]    The sensor may be coupled with an electronic detection device to determine the amount of luminance the forward looking light sensor comes in contact with. In certain cases, the forward looking light sensor&#39;s detected light may be utilized to adjust the luminance. A forward looking light sensor, and specifically a logarithmic forward looking light sensor, may be employed to perform an adjustment of an electronic display or a heads-up display (HUD). 
         [0003]    In conventional technologies, a methodology proposed by Dr. Silverstein has been disclosed to employ linearly sensed light to adjust a display based on the sensed light. As noted in the related applications, new concepts employing several sensors as well as logarithmic sensors are proposed. 
         [0004]    Dr. Silverstein methodology recommended a lens that attenuates incident light as a function of the cosine squared of the angle of incidence of light to the sensor. In employing a lens based solution, the solution may become costly and complex. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0005]    The detailed description refers to the following drawings, in which like numerals refer to like items, and in which: 
           [0006]      FIG. 1  illustrates an example of a forward looking light sensor according to the aspects disclosed herein. 
           [0007]      FIGS. 2( a ), ( b ), ( c ), and ( d )  illustrate an example of the forward looking light sensor shown along with light rays. 
           [0008]      FIGS. 3( a ) and ( b )  illustrate graphs of the normalized function employing the light sensor of  FIG. 1  with regards to a cosine function. 
           [0009]      FIGS. 4( a ) and ( b )  illustrate an example implementation of the sensor of  FIG. 1 . 
       
    
    
     SUMMARY 
       [0010]    A forward looking light sensor is described herein. The sensor includes a first light blocking material; a second light blocking material; and a light sensor with a first surface and a second surface. The first light blocking material is disposed on the first surface of the light sensor and the second light blocking material is disposed on the first surface of the light sensor, and the first light blocking material and the second light blocking forming an aperture. 
       DETAILED DESCRIPTION 
       [0011]    The invention is described more fully hereinafter with references to the accompanying drawings, in which exemplary embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure is thorough, and will fully convey the scope of the invention to those skilled in the art. It will be understood that for the purposes of this disclosure, “at least one of each” will be interpreted to mean any combination of the enumerated elements following the respective language, including combination of multiples of the enumerated elements. For example, “at least one of X, Y, and Z” will be construed to mean X only, Y only, Z only, or any combination of two or more items X, Y, and Z (e.g. XYZ, XZ, YZ, X). Throughout the drawings and the detailed description, unless otherwise described, the same drawing reference numerals are understood to refer to the same elements, features, and structures. The relative size and depiction of these elements may be exaggerated for clarity, illustration, and convenience. 
         [0012]    Forward looking light sensors may facilitate the adjustment of display systems. Further, when implementing the forward looking light sensor as a logarithmic forward looking light sensor, the light adjustment systems may operate in an efficient and advantageous way. 
         [0013]    However, these sensors have conventionally been implemented or proposed to be implemented via a lens-based solution. The employment of lens may be more costly and unnecessarily burdensome. 
         [0014]    Thus, disclosed herein is a logarithmic forward looking light sensor. The aspects disclosed herein are directed to a non-lens based solution. The aspects disclosed herein implement a shadowing technique along with a light sensor and light blocking material. A method for implementing a sensor as disclosed herein is also described. 
         [0015]      FIG. 1  illustrates an example of a forward looking light sensor  100  according to the aspects disclosed herein. As shown in  FIG. 1 , the sensor  100  includes a light sensor  110 , a first light blocking material  120 , and a second light block material  130 . The light blocking materials  120  and  130  each have a thickness of d. Further, the light blocking materials  120  and  130  are placed on a respective edge of the light sensor  110 , and form an aperture  140 . The aperture  140  has a dimension of ‘2×r’. This value of ‘2×r’ will be important in determining the light sensing discussed herein. 
         [0016]      FIGS. 2( a ), ( b ), ( c ), and ( d )  illustrate an example of the forward looking light sensor  100  shown along with light rays  200 . 
         [0017]      FIG. 2( a )  illustrates the sensor  100  with the areas being blocked by the light blocking materials  120  and  130  being blacked out. Thus, the light rays  200  propagate onto the light sensor  110  wherever the aperture  140  allows light to pass on through. 
         [0018]      FIG. 2( b )  illustrates the sensor  100  with the areas being blocked by the light blocking materials  120  and  130  being shown as though the areas would allow light to pass through. As shown, if not for the light blocking material  130 , the amount of distance which would be hit by light rays  200  is also ‘2×r’. This fictional area  220  may be also viewed as a circle. 
         [0019]      FIG. 2( c )  illustrates a diagram  250  illustrating aperture  140  and fictional area  220  overlapping. The radius of each circle is defined as 1 for the sake of explanation. However, depending on the implementation of sensor  100 , this parameter may change. 
         [0020]    The diagram  250  includes two regions S 1  ( 260 ) and S 2  ( 270 ). S 1    260  refers to the area in which the sensor  110  and the aperture  140  overlap and in which the light rays  200  make contact with.  5   2    270  refers to the area light blocking material  130  defines as to where light rays  200  would make contact with (if allowed to pass through). 
         [0021]    The following set of equations prove mathematically how the above-described sensor  100  may effectively be employed as a logarithmic light sensor  100 . Further, they describe a methodology as to how to optimize the dimensions associated with a light sensor to adequately be employed as a cosine squared light sensor. 
         [0000]    
       
      
       x 
       2 
       +y 
       2 
       =r 
       2  
      
     
         [0022]    Solving for the above equation produces: 
         [0000]        y =√{square root over ( r   2   −x   2 )}
 
         [0023]    Performing calculus operation on S 1    260  (a derivative and integration), the following expressions are realized: 
         [0000]    
       
         
           
             
               
                  
                 
                   S 
                   1 
                 
               
               
                  
                 x 
               
             
             = 
             
               y 
               = 
               
                 
                   
                     r 
                     2 
                   
                   - 
                   
                     x 
                     2 
                   
                 
               
             
           
         
       
       
         
           
             
               S 
               1 
             
             = 
             
               
                 
                   ∫ 
                   0 
                   x 
                 
                  
                 
                   
                     
                       
                         r 
                         2 
                       
                       - 
                       
                         x 
                         2 
                       
                     
                   
                    
                   
                       
                   
                    
                   
                      
                     x 
                   
                 
               
               = 
               
                 
                   
                     
                       r 
                       2 
                     
                     2 
                   
                    
                   
                     
                       sin 
                       
                         - 
                         1 
                       
                     
                      
                     
                       ( 
                       
                         x 
                         r 
                       
                       ) 
                     
                   
                 
                 + 
                 
                   
                     x 
                     2 
                   
                    
                   
                     
                       
                         r 
                         2 
                       
                       - 
                       
                         x 
                         2 
                       
                     
                   
                 
               
             
           
         
       
     
         [0024]    Once the area of S 1    260  is ascertained, S 2    270  may be found by taking ¼ th  the area of the circle, and subtracting S 1    260  (as shown by substituting the above equation): 
         [0000]    
       
         
           
             
               
                 
                   
                     S 
                     2 
                   
                   = 
                     
                    
                   
                     
                       
                         π 
                          
                         
                             
                         
                          
                         
                           r 
                           2 
                         
                       
                       4 
                     
                     - 
                     
                       S 
                       1 
                     
                   
                 
               
             
             
               
                 
                   = 
                     
                    
                   
                     
                       
                         π 
                          
                         
                             
                         
                          
                         
                           r 
                           2 
                         
                       
                       4 
                     
                     - 
                     
                       
                         
                           r 
                           2 
                         
                         2 
                       
                        
                       
                         
                           sin 
                           
                             - 
                             1 
                           
                         
                          
                         
                           ( 
                           
                             x 
                             r 
                           
                           ) 
                         
                       
                     
                     - 
                     
                       
                         x 
                         2 
                       
                        
                       
                         
                           
                             r 
                             2 
                           
                           - 
                           
                             x 
                             2 
                           
                         
                       
                     
                   
                 
               
             
           
         
       
     
         [0025]    The total overlap of the area may be determined by multiplying the above relationship by 4, to produce: 
         [0000]    
       
         
           
             
               A 
               o 
             
             = 
             
               
                 π 
                  
                 
                     
                 
                  
                 
                   r 
                   2 
                 
               
               - 
               
                 2 
                  
                 
                     
                 
                  
                 
                   r 
                   2 
                 
                  
                 
                   
                     sin 
                     
                       - 
                       1 
                     
                   
                    
                   
                     ( 
                     
                       x 
                       r 
                     
                     ) 
                   
                 
               
               - 
               
                 2 
                  
                 
                     
                 
                  
                 x 
                  
                 
                   
                     
                       r 
                       2 
                     
                     - 
                     
                       x 
                       2 
                     
                   
                 
               
             
           
         
       
     
         [0026]    The center of the overlap area of the two circles shown in  FIG. 2( c )  may be represented by x 0 . This may be used to define x: 
         [0000]    
       
         
           
             x 
             = 
             
               
                 x 
                 o 
               
               2 
             
           
         
       
     
         [0027]    Which is then substituted into the above area equation: 
         [0000]    
       
         
           
             
               A 
               o 
             
             = 
             
               
                 π 
                  
                 
                     
                 
                  
                 
                   r 
                   2 
                 
               
               - 
               
                 2 
                  
                 
                     
                 
                  
                 
                   r 
                   2 
                 
                  
                 
                   
                     sin 
                     
                       - 
                       1 
                     
                   
                    
                   
                     ( 
                     
                       
                         x 
                         o 
                       
                       
                         2 
                          
                         
                             
                         
                          
                         r 
                       
                     
                     ) 
                   
                 
               
               - 
               
                 
                   x 
                   o 
                 
                  
                 
                   
                     
                       r 
                       2 
                     
                     - 
                     
                       
                         ( 
                         
                           
                             x 
                             o 
                           
                           2 
                         
                         ) 
                       
                       2 
                     
                   
                 
               
             
           
         
       
     
         [0028]    As shown in  FIG. 2( d ) , the sensor  200  is shown with additional incident of light angles. The incident of light  280  may be substituted into the following the equations to further derive the area: 
         [0000]    
       
         
           
             
               x 
               o 
             
             = 
             
               d 
                
               
                   
               
                
               tan 
                
               
                   
               
                
               θ 
             
           
         
       
       
         
           
             
               A 
               o 
             
             = 
             
               
                 π 
                  
                 
                     
                 
                  
                 
                   r 
                   2 
                 
               
               - 
               
                 2 
                  
                 
                     
                 
                  
                 
                   r 
                   2 
                 
                  
                 
                   
                     sin 
                     
                       - 
                       1 
                     
                   
                    
                   
                     ( 
                     
                       
                         d 
                          
                         
                             
                         
                          
                         tan 
                          
                         
                             
                         
                          
                         θ 
                       
                       
                         2 
                          
                         
                             
                         
                          
                         r 
                       
                     
                     ) 
                   
                 
               
               - 
               
                 d 
                  
                 
                     
                 
                  
                 tan 
                  
                 
                     
                 
                  
                 θ 
                  
                 
                   
                     
                       r 
                       2 
                     
                     - 
                     
                       
                         ( 
                         
                           
                             d 
                              
                             
                                 
                             
                              
                             tan 
                              
                             
                                 
                             
                              
                             θ 
                           
                           2 
                         
                         ) 
                       
                       2 
                     
                   
                 
               
             
           
         
       
     
         [0029]    This is referred to as the normalized function, and in  FIGS. 3( a ) and ( b ) , and explanation will be shown as to why this relationship proves that the sensor  100  is an adequate substitute for a sensor to be employed in the Silverstein relationship. 
         [0000]    
       
         
           
             
               A 
               o 
             
             = 
             
               1 
               - 
               
                 
                   2 
                   π 
                 
                  
                 
                   
                     sin 
                     
                       - 
                       1 
                     
                   
                    
                   
                     ( 
                     
                       
                         d 
                          
                         
                             
                         
                          
                         tan 
                          
                         
                             
                         
                          
                         θ 
                       
                       
                         2 
                          
                         
                             
                         
                          
                         r 
                       
                     
                     ) 
                   
                 
               
               - 
               
                 
                   d 
                   
                     π 
                      
                     
                         
                     
                      
                     
                       r 
                       2 
                     
                   
                 
                  
                 tan 
                  
                 
                     
                 
                  
                 θ 
                  
                 
                   
                     
                       r 
                       2 
                     
                     - 
                     
                       
                         ( 
                         
                           
                             d 
                              
                             
                                 
                             
                              
                             tan 
                              
                             
                                 
                             
                              
                             θ 
                           
                           2 
                         
                         ) 
                       
                       2 
                     
                   
                 
               
             
           
         
       
     
         [0030]    The above equation may be solved to produce graphs  300  and  350  to find an optimal ratio of d to r. Once the ratio is known, a sensor  100  may be spaced accordingly. 
         [0031]      FIGS. 3( a ) and ( b )  illustrate graphs  300  and  350  of the normalized function  310  explained above with regards to a cosine function  320 . As shown, the normalized function  310  is an approximation of the cosine function. 
         [0032]    Referring to  FIG. 3( b ) , the normalized function  310  is multiplied with a E cos(Θ), and produces plot  340 . This relationship is defined by the following expression: 
         [0000]    
       
         
           
             
               E 
               M 
             
             = 
             
               E 
                
               
                   
               
                
               cos 
                
               
                   
               
                
               
                 θ 
                  
                 
                   [ 
                   
                     1 
                     - 
                     
                       
                         2 
                         π 
                       
                        
                       
                         
                           sin 
                           
                             - 
                             1 
                           
                         
                          
                         
                           ( 
                           
                             
                               d 
                                
                               
                                   
                               
                                
                               tan 
                                
                               
                                   
                               
                                
                               θ 
                             
                             
                               2 
                                
                               
                                   
                               
                                
                               r 
                             
                           
                           ) 
                         
                       
                     
                     - 
                     
                       
                         d 
                         
                           π 
                            
                           
                               
                           
                            
                           
                             r 
                             2 
                           
                         
                       
                        
                       tan 
                        
                       
                           
                       
                        
                       θ 
                        
                       
                         
                           
                             r 
                             2 
                           
                           - 
                           
                             
                               ( 
                               
                                 
                                   d 
                                    
                                   
                                       
                                   
                                    
                                   tan 
                                    
                                   
                                       
                                   
                                    
                                   θ 
                                 
                                 2 
                               
                               ) 
                             
                             2 
                           
                         
                       
                     
                   
                   ] 
                 
               
             
           
         
       
     
         [0033]    Graph  350  shows plot  340  (the above expression) significantly matches a cosine squared function  330 . As explained in the Silverstein methodology (which is described in a reference submitted along with this application), a sensor that provides a significant cosine squared property is an ideal sensor for employment in luminance adjustment systems. 
         [0034]      FIGS. 4( a ) and ( b )  illustrate an example implementation of a sensor  100 . The distances are merely exemplary and are not limiting to other implementations of sensor  100 . 
         [0035]    As shown in  FIGS. 4( a ) and ( b ) , a cross-sectional view  400  is provided. A chip  410  associated with the sensor  110  is shown. On top of the chip  410  is an epoxy layer  420 . The epoxy layer  420  may cause an addition angle of inflection of light rays  200  (as shown by the slight bend in  FIG. 4( a ) ). However, when employing approximately 0.3 mm of clear epoxy, experimental results have shown the epoxy  420  does not significantly affect the results. 
         [0036]      FIG. 4( b )  illustrates a top overview of the sensor  100 . The distances and dimensions (in millimeters) provided below were experimentally shown to maximize the sensor  100  as a suitable candidate to employ with various adjustment methods of light known in the art. 
         [0037]    It will be apparent to those skilled in the art that various modifications and variation can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.