Method for reducing glare from light sources through windscreens

Abstract

A method of reducing glare may include sensing a first light source with a second vehicle, and sensing a second light source with a first vehicle and oscillating a first light source ICF between a substantially opaque state and a substantially clear state on a first schedule. A second windscreen ICF may be oscillating between the substantially opaque state and the substantially clear state on a second schedule different from the first schedule. A position of the light source may be sensed and an eye position of the occupant estimated. An intersecting region of the selectively-darkenable ICF, which is located substantially along a line from the position of the light source to the eye position, is calculated. The intersecting region of the ICF is darkened, such that a reduced amount of light from the light source passes through the intersecting region.

1 . A method for reducing glare through a windscreen from a light source to an occupant's eye, wherein the windscreen is covered with a selectively-darkenable intensity control film (ICF), the method comprising:
 sensing a position of the light source;   estimating an eye position of the occupant;   calculating an intersecting region of the selectively-darkenable ICF, wherein the intersecting region is located substantially along a line from the position of the light source to the estimated eye position; and   darkening the intersecting region, such that a reduced amount of light from the light source passes through the intersecting region.   
     
     
         2 . The method of  claim 1 , further comprising:
 sensing the eye position of the occupant; and   wherein the intersecting region of the windscreen is calculated based upon the sensed eye position instead of the estimated eye position.   
     
     
         3 . The method of  claim 2 ,
 wherein the selectively-darkenable ICF further includes a matrix of selectively-darkenable ICF cells;   determining which of the ICF cells has a center nearest to the intersecting region; and   wherein darkening the intersecting region includes darkening the ICF cell determined to be nearest to the intersecting region.   
     
     
         4 . The method of  claim 2 , wherein darkening the intersecting region includes darkening a plurality of the ICF cells encompassing the intersecting region. 
     
     
         5 . The method of  claim 4 , wherein the light source is moving relative to the windscreen, and further comprising:
 sensing a new position of the light source;   calculating a new intersecting region of the selectively-darkenable ICF, wherein the new intersecting region is located substantially along a line from the new position of the light source to the sensed eye position; and   darkening the new intersecting region by darkening a plurality of the ICF cells encompassing the new intersecting region, such that a reduced amount of light from the light source passes through the new intersecting region.   
     
     
         6 . A method for reducing glare between a first vehicle and a second vehicle, wherein the first vehicle has a first light source with a first light source intensity control film (ICF) and a first windscreen with a first windscreen ICF, and the second vehicle has a second light source with a second light source ICF and a second windscreen with a second windscreen ICF, the method comprising:
 sensing the first light source with the second vehicle, and sensing the second light source with the first vehicle;   oscillating the first light source ICF between a substantially opaque state and a substantially clear state on a first schedule; and   oscillating the second windscreen ICF between the substantially opaque state and the substantially clear state on a second schedule different from the first schedule.   
     
     
         7 . The method of  claim 6 , wherein the second schedule is one hundred eighty degrees out of phase from the first schedule, such that the first light source ICF is in the substantially opaque state while the second windscreen ICF is in the substantially clear state. 
     
     
         8 . The method of  claim 7 , further comprising:
 oscillating the first windscreen ICF between the substantially opaque state and the substantially clear state on the first schedule; and   oscillating the second light source ICF on the second schedule, such that the first windscreen ICF is in the substantially opaque state while the second light source ICF is in the substantially clear state.   
     
     
         9 . The method of  claim 8 , further comprising:
 sensing magnetic north;   determining a first offset angle for the first vehicle relative to magnetic north;   determining a second offset angle for the second vehicle relative to magnetic north;   calculating the first schedule as a function of the first offset angle; and   calculating the second schedule as a function of the second offset angle.   
     
     
         10 . The method of  claim 9 , further comprising:
 monitoring a common clock cycle;   wherein calculating the first schedule includes phase lagging the first offset angle from the common clock cycle; and   wherein calculating the second schedule includes phase lagging the second offset angle from the common clock cycle.   
     
     
         11 . The method of  claim 6 ,
 wherein the first schedule has a first frequency and the second schedule has a second frequency different from the first frequency; and   wherein the second frequency is between one to thirty percent different from the first frequency.