| 摘要 |
An afocal catadioptric light beam generator usually consists of a concave mirror, a primary light source and a combination of lenses. The present generator - which is used to supply light to optical fibres in signalling systems for railways and motorways - has a combined light source and mirror and only one lens. - The light source is a incandescent lamp with a spherical glass envelope that is partly silvered to provide the concave mirror. The beam from the lamp passes through a hemispherical plano-convex lens to form a converging beam that is within the acceptance angle of the fibres in a bundled fibre cable. The generator is housed in a simple ventilated casing made from thin sheet metal.(0/2)
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