How to know the quality of the lens set used in a microscope
Microscope several axes in the same straight line (i.e. optical axis) on the hollow metal cylinder, or Olympus microscope parallel arrangement and the centre of a circular hole in the metal diaphragm is an axisymmetric structure of the electrode. When they add a certain voltage, they can produce an axisymmetric distribution of the electrostatic field. This flutter electric field can make the microscope electron focusing imaging, so it is called electrostatic microscope. There are many different types of electrostatic lenses. If the potential distribution on the axis of symmetry generated after the application of voltage as a feature, Olympus can be roughly divided into four categories of microscopes.
Single potential lens a microscope on the left and right sides of the axis of Olympus potential is constant and equal: immersion lens a microscope on the left and right sides of the axis of the potential is a constant but the value is not equal to a single diaphragm lens (also known as the membrane aperture lens) a lens role is concentrated in the vicinity of the diaphragm aperture. The intensity of the electric field on the axis of each of the two rules of the microscope is constant. The circular aperture of the diaphragm alone is of little use, but it can often be used as a component of some complex lenses.
Immersion Objective A object emitting electrons is directly immersed in the electric field of this type of microscope, and the on-axis potential on the other (i.e., image-side) side of the Nikon lens is constant. With the exception of class 4, the other three types of electron-open lenses can be regarded as microscopes, and thus their object-side focal people and image-side focal offsets can be deduced. The formula for the focal lengths of the two types of lenses of class 1,2 is.
It is not difficult to prove that the focal lengths in monopotential and immersion lenses are constantly positive, which means that these Nikon microscopes always converge. While single diaphragm lenses are can constitute diverging lenses, as for the performance of immersion objective lenses to be analysed on a case-by-case basis. An example of a typical type of drum is the electron gun used in Nikon microscopes and other electron beam tubes. Its function is to form an electron beam with a certain cross-sectional shape and current intensity.
