Reading of Information in radiation emitted from storage media

摘要

An arrangement for detecting an image on a phosphorescent foil has two light conductors which lead to a common photomultiplier. The light conductors are spaced from one another by a small gap which allows a laser beam to pass between the conductors and excite the foil. The light conductors have flat end faces for the admission of light into the conductors, and the end faces are directed towards the foil as well as the gap. The end faces make an angle of 10 to 30 degrees with the foil. The light conductors are designed so that the greater part of impinging radiation is admitted into and travels the length of a conductor only when the path of the radiation and a normal to the respective end face define an angle which is equal to or less than the acceptance angle of the conductor. Each end face has an edge remote from the gap, and a location at which the laser beam impinges the foil defines a plane with a location on either edge. The impingement location of the laser beam defines a line with each edge location, and each line makes an angle equal to or less than the acceptance angle with a normal to the respective end face. A reflector can be mounted adjacent either edge to reflect light emitted from the foil towards the end faces.