| 摘要 |
<p>An optical system having a light source means and a detector means for detecting one or more articles which by means of a conveyor move or are temporarily stationary under the means, where said article(s) has/have at least one reflective portion, and where light is emitted towards the article(s) from the light source means and reflected back towards the detector means. The optical system is characterised in that at a distance above the conveyor there is provided a lens, that the light source means and the detector means are located in or essentially in the same plane which is parallel to the plane of the lens and coincident with the focal plane of the lens, and that the optical axis of the lens is coincident with an axis perpendicular to the focal plane and located halfway between the light source means and the detector means.</p> |
