Patent ID: 8167434

Claim:
Light projection system ( 10 , 12 , 14 , 16 , 18 ) for use in conjunction with a display device ( 40 ), the light projection system ( 10 , 12 , 14 , 16 , 18 ) comprising: a light source ( 30 ) for emitting light being modulated by video and/or audio content of the display device ( 40 ), and a longitudinal light guide ( 20 , 22 , 24 ) for guiding light emitted by the light source ( 30 ) substantially along a longitudinal axis ( 26 ) and for projecting the light propagating through the longitudinal light guide ( 20 , 22 , 24 ) on a projection surface ( 50 , 52 ), the longitudinal light guide ( 20 , 22 , 24 ) comprising: a light input window ( 28 ) arranged at an end-portion of the longitudinal light guide ( 20 , 22 , 24 ), the light input window ( 28 ) being arranged for coupling in light from the light source ( 30 ) into the longitudinal light guide ( 20 , 22 , 24 ) substantially along the longitudinal axis ( 26 ), and a plurality of light out-coupling elements ( 60 , 62 , 64 ) contained within the longitudinal light guide for projecting the light on the projection surface ( 50 , 52 ), at least one of the plurality of light out-coupling elements ( 60 , 62 , 64 ) comprising sub-sets ( 70 a , 70 d ; 72 a , 72 d ; 74 a , 74 d ) of light out-coupling elements ( 60 , 62 , 64 ), a particular sub-set ( 70 a , 70 d ; 72 a , 72 d ; 74 a , 74 d ) being arranged for substantially illuminating a particular area ( 50 a , 50 d ) of the projection surface ( 50 , 52 ), a luminous intensity emitted by the particular sub-set ( 70 a , 70 d ; 72 a , 72 d ; 74 a , 74 d ) being dependent on a distance (d a , d d ) along a straight line between the particular sub-set ( 70 a , 70 d ; 72 a , 72 d ; 74 a , 74 d ) and the particular area ( 50 a , 50 d ), and/or on an angle between the straight line and normal of the projection surface ( 50 , 52 ).