The aim of confocal microscopy is the suppression of light from out-of-focus planes. This is realized firstly by a point illumination in the focal plane and secondly by a pinhole in the conjugate plane of the detection beam path.
Due to the point illumination and detection only information from a single point is determined at a time. In order to generate an image the sample is scanned point –by-point and line-by-line.
The advantages of confocal microscopy over conventional wide-field microscopy are an improved resolution in the lateral plane, a high discriminatory power in axial direction, a reduced background signal, and the opportunity to collect serial optical sections from different focal planes to generate depth profiles or 3D images.