Light vs Electron Microscopes |Electron Microscope vsOptical显微镜
Light (optical) microscope and electron microscope are two main types of microscopes. This article will discuss the functionality of those two microscopes, their similarities and finally the differences between them.
Light (Optical) Microscope
显微镜是一种仪器,旨在看到物体,它太小,无法用肉眼看。最简单的光学显微镜是简单的镜头显微镜,仅由单个双螺旋透镜组成。可以使用如此简单的镜头显微镜放大对象。但是,放大功率很小,图像的失真很高。后来,开发了化合物显微镜。传统的光学显微镜具有多个光学元素。即,镜子,显微镜载玻片,物镜镜头和目镜镜头。凹面的镜子从外部光源中收集光,并将光聚焦在放置在幻灯片上的样品上。幻灯片由透明玻璃制成。光线穿过玻璃的光线通过样品到达物镜。 The objective lens then refocuses the light, which is gathered by the eyepiece. The eyepiece creates an image to be observed by the eye or a camera. It must be noted that only samples, which allows light to travel through it, can be observed using such a microscope. Live samples such as bacterial cultures and fungi can be observed using such a microscope. Due to technical limitations only resolutions up to about 200 nm are possible using traditional lens systems. The effective magnification of a traditional microscope is about 2000x.
Electronic Microscope
As discussed in the optical microscope, a microscope must satisfy several requirements. These requirements are an observation method, a focusing method and how the final image is produced. The observation method or analysis method used in the electron microscope is a beam of electrons. When a beam of electrons hit a certain material the beam is scattered by the material. This scattering pattern is the basis of the final image formed. The electron beam is focused using electromagnetic coils, which are analogous to the optical lenses in the optical microscope. The focused electron beam is targeted to every point of the sample to get the diffraction pattern of the whole sample. This diffraction pattern is then processed, as an optical image, to be seen by the human eye or to be studied using a computer. Since every atom will scatter the electrons, a vacuum is required to minimize the noise coming from the air molecules. Since an electron beam will obviously kill any living species, and a vacuum is required, a living sample cannot be observed using the electron microscope. The magnification of an electron microscope can be as high as 10,000,000x where the resolution is 50 pm.
What is the difference between electron microscope and light (optical) microscope? • Electron microscope uses an electron beam, while an optical microscope uses a light beam. • The maximum magnification of the optical microscope is about 2000x, where the maximum magnification of the electron microscope is about 10,000,000x. |
Leave a Reply