In Early times on microscopists relied on oil lamps and natural sunlight to offer an external source of illumination for their ancient (however regularly amazingly precise) microscopes. They frequently in use rather inventive methods of gathering light, such as reflection from a large white board or spreading of sunlight on a cloudy day. Unfortunately, these primitive methods did not provide reliable illumination and regularly the area of field illumination to the highest degree exceeded the numerical space of the objective, causing glare and flooding