| 摘要 |
An apparatus for measuring retro-reflective properties of a surface (1), i.e. the ability of the surface to reflect light in essentially the same direction as the incidence direction, comprising a light source (2) for emitting light onto the surface (1) and a detector (3) for receiving the light reflected by the surface (1), the light source and the detector communicating with a separate photoconductor. According to the invention, a collimating lens (4) is provided, the ends of the photoconductors being juxtaposed in the focal plane of the lens (4). As a result, the measuring geometry can be easily reproduced. The measuring angle is entirely determined by the distance between the optical fibres. This distance can be reproduced and controlled by means of simple tools. Subsequent to manufacture and control, the measuring geometry is unaffected by any environmental influences. |
