Main Parts and Their Functions for Laser Scanning Confocal Microscope
① Illumination Pinhole Function: After laser passes through the illumination pinhole, a point light source is formed. This point light source features strong directivity, low divergence, high brightness, high spatial and temporal coherence, and plane-polarized excitation. Together with the detector pinhole and focal plane, it constitutes a confocal assembly.
② Beam Splitter Function: Separates the fluorescence excited from the sample from other non-signal light.
③ Objective Lens
④ Focal Plane Function: The point laser source illuminates the object and focuses at the focal plane. The fluorescence-labeled sample emits fluorescence to form a focal spot. After processing by a series of devices including the objective lens and beam splitter, the light spot is focused at the illumination pinhole and detector pinhole respectively. This is the origin of the term "confocal".
⑤ Detector Pinhole Function: It acts as a spatial filter. It blocks scattered light outside the focal plane and scattered light beyond the focal spot on the focal plane to the maximum extent. It ensures that all fluorescence signals received by the detector pinhole originate exactly from the focal spot position on the sample. Therefore, the diffracted focused spot on the sample and the image spot at the detector pinhole carry identical information (two-point conjugation).
⑥ Photomultiplier Tube (Detector) Function: It receives the optical signal passing through the pinhole, converts it into an electrical signal and transmits the signal to a computer, so that a clear full image of the focal plane can be displayed on the screen.
⑦ Laser The rapid development of laser scanning confocal microscopy relies heavily on advances in lasers. Different lasers can be selected according to research requirements, such as ArUV(351,364nm), HeCd(442nm), AR(457,488,514nm), ArKr(488,568,647nm), Kr(56…) and so on.
⑧ Multi‑Fluorescence Channel Function: Equipped with multiple fluorescence channels to enable multi-labeling of samples simultaneously.
