Differences and similarities between phase contrast, inverted and conventional light microscopes
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 an idea was proposed by the American scholar Marvin Minsky in 1953, and it took 30 years of development before a confocal microscope was developed using a laser as a light source, in line with Marvin Minsky's ideal.
Inverted microscope: The composition is the same as that of an ordinary microscope, except that the objective lens and the illumination system are reversed, with the former under the stage and the latter on top of the stage. It is convenient for operation and installation of other related image acquisition equipment.
A light microscope is a microscope that uses optical lenses to produce an image magnification effect. Light incident from an object is magnified by at least two optical systems (objective and eyepiece). The objective lens first produces a magnified image, and the human eye observes this magnified image through an eyepiece that acts as a magnifying glass. A typical light microscope has several interchangeable objectives so that the observer can change the magnification as needed. These objectives are generally housed on a rotatable objective disc, which can be turned to give easy access to different eyepieces in the optical path. Physicists discovered the law between magnification and resolution, people know the resolution of the optical microscope is a limit, the resolution of this limit limits the magnification of the unlimited increase in magnification, 1600 times the highest limit of magnification of optical microscopes, so that the application of morphology in many areas by a great deal of restriction.
The resolution of an optical microscope is limited by the wavelength of the light, which generally does not exceed 0.3 microns. The resolution can be increased if the microscope uses ultraviolet light as a light source or if the object is placed in oil. This platform became the basis for building other optical microscopy systems.
