出典:Wiktionary
出典:Wikipedia
出典:『Wikipedia』 (2011/05/11 21:21 UTC 版)
A retroreflector (sometimes called a retroflector or cataphote) is a device or surface that reflects light back to its source with a minimum scattering of light. An electromagnetic wave front is reflected back along a vector that is parallel to but opposite in direction from the wave's source. The device or surface's angle of incidence is greater than zero. This is unlike a planar mirror, which does this only if the mirror is exactly perpendicular to the wave front, having a zero angle of incidence.