Structure, Working Principle, Characteristics and Application Scope of Stereomicroscopes
A stereomicroscope, also known as a dissecting microscope or operating microscope, is a visual instrument that produces erect stereoscopic images.
Its optical working principle: a shared primary objective forms an image of the object. The two light beams from this image are separated by two sets of intermediate objectives (zoom lenses) at a certain angle, called the stereoscopic angle, which is generally 12°–15°. The beams then form separate images through their respective eyepieces. Magnification is adjusted by changing the spacing between the intermediate lens groups. It adopts a dual-channel optical path; the left and right light beams inside the binocular tubes are not parallel but form an included angle, delivering a stereoscopic image to the left and right eyes. Essentially, it consists of two monocular microscopes arranged side by side. The optical axes of the two tubes simulate the viewing angle of human binocular vision, thereby generating a three-dimensional stereoscopic image.
Its features include a large field diameter and great depth of field, facilitating observation of all layers of the specimen. Although its magnification is lower than that of conventional microscopes, it provides a long working distance and erect images for convenient practical operation. The erect image is produced by prisms installed below the eyepieces, which invert the image.
To meet practical application requirements, stereomicroscopes can be equipped with a wide range of optional accessories. For higher magnification, eyepieces and auxiliary objectives with greater magnifying power can be selected. Digital interfaces allow connection with digital cameras, video cameras, electronic eyepieces and image analysis software to build a digital imaging system for computer-based analysis and processing. The illumination system includes reflected light and transmitted light, with light sources such as halogen lamps, ring lights, fluorescent lamps and cold light sources.
Thanks to these optical principles and characteristics, stereomicroscopes are widely used in industrial production and scientific research. In biology and medicine, they are applied for section preparation and microsurgery. In industry, they are used for observation, assembly and inspection of tiny components and integrated circuits.
