Microscopes - Confocal microscope

A confocal microscope is a special light microscope. Unlike conventional light microscopy, it does not illuminate the entire specimen, but only a fraction of it at any given time, in many cases only a small spot of light. This illumination is rastered over the specimen piece by piece. Thus, no complete image is formed in the microscope at any time. Consequently, the light intensities of the reflected light or light emitted by fluorescence are measured successively at all locations of the area to be imaged, so that a subsequent construction of the image is possible. A pinhole is placed in the path of the detected light, allowing light from the sharply imaged area to pass through and blocking light from other planes. As a result, only light from a small volume around the focal point reaches the detector, producing high-contrast optical cross-sectional images that contain almost only light from a narrow slice around each focal plane.