Incidence angle light attenuator for light transmissive panels

Apparatus for controlling light passage through a panel as a function of incident light angle comprising:

• a light transmissive panel having first and second surfaces spaced apart by the thickness of said panel;
• a first plurality of light polarizing elements formed as elongated strips each having an absorption axis at least in the middle thereof aligned in a first predetermined direction, said absorption axis generally continuously varying toward a second absorption axis from the middle of the strips to opposite edges thereof;
• a second plurality of light polarizing elements formed as elongated strips each having an absorption axis at least in the middle thereof aligned in the second predetermined direction, said second plurality of elements being alternately arranged with said first elements to form a first polarized sheet, said first sheet being overlayed on said first surface of said panel, said absorption axis of said second plurality of strips varying toward the first absorption axis from the middle of the strips to opposite edge thereof, said absorption axis of said second strips at their respective edges being substantially identical to the absorption axis of said first strips at adjacent edges thereof such that the absorption axis varies substantially continuously over said sheet;
• a second polarized sheet substantially identical to said first sheet, said second sheet being overlayed on said second surface of said panel, said first and second sheets being positioned such that light impinging on said panel within a preselected range of incidence angles passes through only areas of similar polarization of said first and second plurality of element sand at least some light impinging at angles outside said preselected range passes through areas of different polarization of said first and second plurality of elements;
• and
• said first and second plurality of elements being selected such that light passing through at least the middle of both of said elements is substantially attenuated.