| 摘要 |
PURPOSE:To prevent the static image of a flying particle from being out of focus on a pickup plane even when the flying route of the flying particle varies along the direction of an optical axis, by providing a parallel light forming means which changes the output light of a pulse light emitting means into a parallel light for illuminating the flying particle. CONSTITUTION:A parallel light forming means 5 which changes a pulse light outputted from a stroboscopic light source 1 into a parallel light for illuminating a flying particle 2 is provided. By this means, a static image is prevented from being out of focus even when the flying route of the flying particle 2 varies in the direction of the optical axis of an obwerving system which is constituted by the stroboscopic light source 1, the parallel light forming means 5 and a solid-state pickup element 4, and thus a focus adjusting mechanism turns unneces sary. |
