Reflective optical baffle concept

Abstract

In the past the optical baffle usually consisted of a cylindrical tube assembly with a black interior vane structure to create a highly absorptive labyrinth to trap and absorb light before it propagated further into the optical system. This type of baffle is well developed and is suitable for a myriad of optical system uses. However, in certain stressing environments or conditions, the black baffle degrades and may fail to absorb a sufficient amount of stray light. To address these conditions, an approach to optical baffle design based on reflection rather than absorption has been developed. Although similar reflective baffle structures have been studied and developed, this new approach utilizes all reflective confocal conic surfaces to reject incident specular energy. Total specular rejection of incident energy is achieved by using a combination of vane surfaces described as oblate spheroids and hyperboloids of one sheet which have common foci at the entrance aperture of the baffle assembly. When surfaces are arrayed in this manner to create a series of baffle vanes, light incident on the vanes is reflected by these surfaces back out of the assembly through the entrance aperture with no specular propagation further into the baffle assembly.