Edge emitter as a directional line source

摘要

A broadband line source that is directional, rugged, compact, spatially and temporally uniform, stable, without the need for warmup, and relatively easy to implement. The source can be in single-color or multi-color, and it can be used, for example, in a scanner. In one embodiment, the line source includes a first thin-film electroluminescent stack with at least a bottom electrode, a top electrode, and a first active film between the two electrodes. The active film generates radiation in an area that has a width and a length, with the length being larger than the width. The length of the area sets the length of the line radiation, which is substantially homogenous along the line. In another embodiment, three of such stacks are encapsulated through thin-film processes by a cap, which sits on a substrate. The cap has one side surface that is more transmissive to radiation. The generated radiation is directed by the cap to be emitted at the more transmissive side surface to produce a single-color or a multi-color line source.