Wilhelm, S., Gröbler, B., Gluch, M., Heinz, H.
Confocal laser scanning microscopy principles. ZEISS Jena

In recent years, the confocal laser scanning microscope (LSM) has become widely established as a research instrument. LSM applications in biology and medicine predominantly employ fluorescence, but it is also possible to use the transmission mode with conventional contrasting methods, such as differential interference contrast (DIC), as well as to overlay the transmission and confocal fluorescence images of the same specimen area. Another important field of application is materials science, where the LSM is used especially in the reflection mode and with such methods as polarization. Confocal microscopes are even used in routine quality inspection in industry. Here, confocal images provide an efficient way to detect defects in semiconductor circuits. The present brochure aims at giving a scientifically sound survey of the special nature of image formation in a confocal LSM. Following a description of the fundamental differences between a conventional and a confocal microscope, the article will set out the special features of the confocal LSM and the capabilities resulting from them. The conditions in fluorescence applications will be given priority treatment throughout.