Biology 2290F/G Lecture Notes - Lecture 2: Phase-Contrast Microscopy, Dichroic Filter, Fluorescence Microscope
20 Apr 2017
School
Department
Course
Professor
Document Summary
First to observe living protozoa and bacteria which he called animalcules . Went on to visualize human red blood cells and sperm. With great skill at grinding lenses, naturally acute eyesight and lots of patience he was able to achieve a magnification of 200x. Objective lens to collect light after it has passed through specimen. Ocular or eyepiece lens to focus image onto eye. Only structures with a high refractive index (ability to bend light) are observable. Higher refractive index will produce more contrast. Typical light microscope magnification is 40 to 1000x. In order to see detail, you need some sort of contrast, which is achieve by a high refractive index (ability to bend light) Resolution: the ability to distinguish between two very closely positioned objects as separate entities. A conventional light microscope usually can"t resolve objects/cellular features that are less than ~0. 2 micrometres apart. Nsin(alpha) = numerical aperture (higher is better)
