subject: Stereo Microscope: Magnifying The Perception [print this page] The stereo microscope is an optical microscope that produces a three-dimensional visualization of the sample being examined by using separate optical paths with two objectives and two eyepieces. It is designed for low magnification observation of a sample using incident light illumination rather than transillumination. A stereo microscope is used in many fields, including health, medical research, biology, government services, education, archeology and police work, among other areas.
A basic stereo microscope consists of stereo head, eyepiece, eyepiece diopter setting, objective lens, focus knob, lighting, rack and pinion focusing, stage clips and a stage plate. The stereoscopic microscope is usually only about 1 or 2 feet high, but it is heavy, sometimes even about 50 lbs. The weight helps in keeping the specimen as still as possible. Most stereo microscopes also come with their own built-in light source, which can further add to the weight. Stereo microscope magnifications can range from as little as 2x up to 300x, but typically might be between 20x and 80x. For most applications, 4x - 20x is enough, but some may require higher magnification.
There are two key types of stereo microscopes. First one is the greenough optical design. This microscope, relatively inexpensive to manufacture, has converging angled optical paths. The second type, which tends to be costlier, has parallel optical paths from the eyepieces to the final objective lens. The optical paths then converge between the final objective and the subject. These microscopes with common main objective (CMO) have wider magnification ranges and allow accessories to be fitted between the eyepieces and objective lens.
Greenough stereo microscopes are usually used for "workhorse" applications, such as printed circuit board inspection, dissecting biological specimens, or similar routine tasks, CMO stereo microscopes are generally used in more complex applications that need high resolution with advanced optical and illumination accessories.
While choosing the appropriate microscope, one must consider several factors like the type of specimen he/she needs to magnify, any special requirements and also the budget. There are stereo microscopes that allow one to move the specimen or even capture images. Many stereo manufacturers offer customized microscopes to meet the requirements of the buyer.
Newer versions of microscopes are entering the market continuously. Researchers are working to develop a stereoscopic microscope that will to integrate with a three-dimensional computer program. A camera is connected to the microscope's images and then stored in a computer for future use. This can reduce the number of slides needed and also allow many people see the same thing at the same time.
