Patent ID: 7374313
Filing Date: 2008-05-20
Classification: G02B

Abstract:
1. A luminaire with improved lateral illuminance control, comprising: a) a light pipe with a longitudinal center; b) light-extraction means applied to a radial swath of the light pipe having a longitudinal portion with a dimension along the length of the light pipe that is centered about a slice of the light pipe; said slice being orthogonal to the longitudinal center, and being located in a propagation plane through which light propagates to a virtual target area that intersects the propagation plane; the light pipe intervening between the radial swath and the target area; c) a first average efficiency point of the light-extraction means in the radial swath corresponding to the minimum distance to the target area being at least approximately a predetermined percentage less than a respective, second average efficiency point of the light-extraction means in the radial swath corresponding to a respective maximum distance to the target area; the predetermined percentage being 20%; and d) the efficiency of the light-extraction means in the radial swath vanes from the first average efficiency point to the second average efficiency point though more than one non-zero value.