Apparatus for illumination stabilization and homogenization

摘要

An illumination device provides temporally, spatially and angularly stable illumination for microscopic evaluations. An arc lamp serves as the light source. An input optical train gathers and focuses the light through an aperture stop to place an image of the arc incident on an input aperture of a light pipe. The magnification of the arc lamp is chosen to reduce the variation due to occlusion. The light pipe spatially homogenizes the light while preserving the angular integrity. An exit window may be placed over the exit aperture of the light pipe to keep dust and debris out of focus. Another optical train receives the spatially homogenized, angularly preserved light and may focus a many arclet images to fill the pupil of a condenser lens. The condenser lens also may focus the exit aperture of the light pipe onto or near the specimen on a microscope slide. A feedback system samples the light and corrects for residual temporal variations by electronically modifying the image as it leaves a CCD. A neutral density filter controls the overall energy passed through the system.