(under subclass 257) Subject matter wherein the modifier includes at least two spaced adjacent modifying means each having at least two plane or curved surfaces of the type
generated by a straight or curved line (the "generatrix"); the means being so arranged relative to each other and to the light source that (a) no two of the surfaces are generated by an extension of the same generatrix, (b) one of the surfaces of one means faces one of the surfaces of the adjacent means, (c) one of the surfaces of each means is exposed to light from the light source, and (d) light from the source is able to pass both surfaces of each means and at least one of the surfaces in a direction parallel or tangent to its generatrix.
(1) Note. A "grid" for purposes of classification in this subclass consists of at least two intersecting pairs of louvers.
(2) Note. The two spaced adjacent means of this subclass may be part of the same element, as for example, a spiral louver.
SEE OR SEARCH THIS CLASS, SUBCLASS:
325, for angularly adjustable louvered or grid type modifiers, per se.
330, for panel type refractor modifiers which may include louvers or grids. 342, for louvered or grid type reflectors, per se.
354, for louvered or grid type translucent or opaque modifiers, per se.
