| 摘要 |
<p>The invention concerns a detector of stains on a transparent plate (1) surface (3). Said detector, arranged on the plate (1) internal surface (2), comprises means emitting (4) a modulated light signal (S) towards the plate (1) inside and means receiving (5) said signal, after it has been reflected on the plate (1) external surface (3). An optical unit (9), made with a material having an index substantially higher than (1), is arranged on the plate (1) internal surface (2). It is made up of at least three faces returning the light signal (14, 15, 18) and an interface (16) with the plate (1) internal surface (2) through optical coupling means (7). Means for deflecting (L1, L2, R1, R2) the signal (S) direct the signal (S) from the emitting means (4) towards the plate (1) and from the unit (9) towards the receiving means (5). At least two reflections (10 to 12), on the plate (1) external surface (1) are produced through the optical coupling means (7) without reflection on said plate (1) internal surface (2).</p> |
