Phase contrast, inverted and conventional light microscopes - differences and similarities
These are optical microscopes, using visible light as a means of detection, unlike electron microscopes, scanning tunnelling microscopes, atomic force microscopes, and so on.
Specifically:
Phase contrast microscopy, also known as phase contrast microscopy. This is because light rays produce a small phase difference as they pass through a transparent sample, and this phase difference can be converted into a change in magnitude or contrast in the image so that it can be used to image. It was invented in the 1930s by Fritz Zelnick in his research on diffraction gratings. For this he was awarded the Nobel Prize in Physics in 1953. It is now widely used to provide contrast images of transparent specimens such as living cells and small organ tissues.
Confocal Microscopy: An optical imaging technique that uses point-by-point illumination and spatial pinhole modulation to remove scattered light from the non-focal plane of a sample, allowing for improved optical resolution and visual contrast compared to traditional imaging methods. Probe light emitted from a point source is focused through a lens onto the object being observed, and if the object is exactly at the focal point, the reflected light should converge back to the light source through the original lens, which is known as confocal, or confocal for short. Confocal microscope in the light of the reflected light on the road with a half-reflective half-lens (dichroic mirror), will have passed through the lens of the reflected light folded in the other direction, in the focus of the focus with a pinhole (Pinhole), the hole is located in the focal point, the baffle plate behind the photomultiplier tube (photomultiplier tube, PMT). It can be imagined that the reflected light before and after the focal point of the detector light through this set of confocal system, will not be able to focus on the small hole, will be blocked by the baffle. So the photometer measures the intensity of the reflected light at the focal point. The significance of this is that a translucent object can be scanned in three dimensions by moving the lens system. Such a concept was proposed by the American scholar Marvin Minsky in 1953, and it took 30 years of development to develop a confocal microscope that met Marvin Minsky's ideals using a laser as a light source.
