摘要 |
A variable spot size illuminator for projecting a variable size spot of light into an illumination plane comprises a source of light, fiberoptic image transmission means having an entrance surface and an exit surface, means for projecting a cone of said light onto said entrance surface, objective lens means for focusing light emerging from said exit surface into said illumination plane, and means for varying the distance between said entrance surface and the vertex of said cone of light. The variable spot size illuminator is useful for projecting a spot of variable size with constant beam convergence in a laser photocoagulator. |