Both faceplates and tapers are used as couplers for CCD chips. In the case of faceplates , the fiber optic is used as a cover window for the CCD surface and performs the following functions:
protects the CCD surface from physical damage; provides an x-ray absorption layer to protect the CCD from x-ray damage; allows for direct 1:1 coupling with other optical devices; provides a surface for direct coating (such as a phosphor screen); and provides for more efficient coupling than with a lens.
In addition, fiber optic tapers offer these additional benefits:
As opposed to the alternatives of direct coupling and lens coupling to the CCD, fiber optics offer some attractive alternatives.