The use of a compound objective/eyepiece combination allows for much higher magnification. That image is then magnified by a second lens or group of lenses (called the eyepiece) that gives the viewer an enlarged inverted virtual image of the object (image 2). The use of a single convex lens or groups of lenses are found in simple magnification devices such as the magnifying glass, loupes, and eyepieces for telescopes and microscopes.Ĭompound microscope Diagram of a compound microscopeĪ compound microscope uses a lens close to the object being viewed to collect light (called the objective lens), which focuses a real image of the object inside the microscope (image 1). Compound microscopes can be further divided into a variety of other types of microscopes, which differ in their optical configurations, cost, and intended purposes.Ī simple microscope uses a lens or set of lenses to enlarge an object through angular magnification alone, giving the viewer an erect enlarged virtual image. The vast majority of modern research microscopes are compound microscopes, while some cheaper commercial digital microscopes are simple single-lens microscopes. A compound microscope uses a system of lenses (one set enlarging the image produced by another) to achieve a much higher magnification of an object. A simple microscope uses the optical power of a single lens or group of lenses for magnification. There are two basic types of optical microscopes: simple microscopes and compound microscopes. While larger magnifications are possible no additional details of the object are resolved.Īlternatives to optical microscopy which do not use visible light include scanning electron microscopy and transmission electron microscopy and scanning probe microscopy and as a result, can achieve much greater magnifications. The maximum magnification power of optical microscopes is typically limited to around 1000x because of the limited resolving power of visible light. Phase-contrast imaging can be used to increase image contrast by highlighting small details of differing refractive index.Ī range of objective lenses with different magnification are usually provided mounted on a turret, allowing them to be rotated into place and providing an ability to zoom-in. Polarised light may be used to determine crystal orientation of metallic objects. Transparent objects can be lit from below and solid objects can be lit with light coming through ( bright field) or around ( dark field) the objective lens. The sample can be lit in a variety of ways. A camera is typically used to capture the image ( micrograph). In high-power microscopes, both eyepieces typically show the same image, but with a stereo microscope, slightly different images are used to create a 3-D effect. The object is placed on a stage and may be directly viewed through one or two eyepieces on the microscope. Basic optical microscopes can be very simple, although many complex designs aim to improve resolution and sample contrast. Optical microscopes are the oldest design of microscope and were possibly invented in their present compound form in the 17th century. The optical microscope, also referred to as a light microscope, is a type of microscope that commonly uses visible light and a system of lenses to generate magnified images of small objects. Scientist using an optical microscopes in a laboratory
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