Microscopes

Instruments designed to magnify samples or specimens with a light source; includes compound, infrared, simple, and stereo microscopes as well as lamps and accessories.

Compound microscopes are used to view images of small objects on glass slides. Magnification can range from 40x to 1000x and is achieved by multiple convex lenses in the eyepieces and in magnifying objectives. In upright microscopes, the objective lens is closest to the object, and the eyepiece further enlarges the image. A light source illuminates the object to produce a two-dimensional image.

Inverted microscopes’ light sources and condensers are above the object, with the objective lens pointing up toward the object to be viewed. They are commonly used to observe cells growing on the bottom surface of a culture flask or used for micromanipulations or metallurgical applications.

Stereo microscopes (also called dissecting microscopes) offer lower magnifications and reflect light from an object’s surface. Separate right and left light paths provide slightly different viewing angles, creating a 3D sample view. Stereo microscopes are used to examine the surfaces of solid specimens or for dissection or microsurgery. In addition, they are used in manufacturing for inspection and quality control.

Digital microscopes create digital or electronic images and may be any type of microscope. Many digital microscopes also have a separate screen to preview the images. USB computer microscopes plug into a USB port. Instead of using an eyepiece, the viewer examines the specimen via the computer monitor or TV screen. Most of these microscopes are handheld and can save images as files or videos. However, their low-level magnification, and adequate illumination can be a problem.

Pocket microscopes are handheld, durable, and useful for field work. Sizes vary, and some are the size of an ink pen. Most use natural light or are battery-powered, with 25x to 100x magnification.