| 摘要 |
The present invention concerns a retroreflective device that is composed of a number of optical microrelief elements. The retroreflector includes a first layer (12) consisting of a number of densely packed coplanar microrelief lenses, a second layer (14) consisting of a number of densely packed coplanar microrelief mirrors, coated with a reflecting layer (16) on the side opposite to the microrelief lenses, and a third layer (17) in-between the first and the second layer. The first and the second layer are oriented so as to exhibit a multitude of element pairs, each in the form of a microrelief lens (12) and a microrelief mirror (14) with essentially coinciding optical axes. The distance between a microrelief lens (12) and the corresponding microrelief mirror (14) is such that the microrelief mirror is located essentially in the focal plane of the microrelief lens. The microrelief mirror has its equivalent centre of curvature essentially in the centre of the corresponding microrelief lens. |
