Water immersion objective
- Water immersion objective
In light microscopy, a water immersion objective is a specially designed objective lens used to increase the resolution of the microscope. This is achieved by immersing both the lens and the specimen in water which has a higher refractive index than air, thereby increasing the numerical aperture of the objective lens.
Applications
Water immersion objectives are used not only at very large magnifications that require high resolving power, but also of moderate as there are water immersion objectives as low as 20X. Objectives with high power magnification have short focal lengths, facilitating the use of water. The water is applied to the specimen (conventional microscope), and the stage is raised, immersing the objective in water. Sometimes with water diping objectives, the objective is directly immersed in the solution of water which contains the specimens to look at. Electrophoretic preparations used for instance in the cases of Comet Essay can benefit largelly with water objectives.
The refractive indices of the water and of the glass in the first lens are different but less than it would be the cases between air and glass as it will be the case with a non immersion objective, which means that the refraction of light will be small upon entering the lens.
Correction collar
Unlike oil, water does not have the same or near identitical refractive value as the cover slip glass, so a correction collar is needed to be able to variate for its thickness. Lens without correction collar generally are made for the use of a 0.17 mm cover slip.
ee also
*Oil immersion objective
*Microscopy
*Optical microscope
*Index-matching material
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Look at other dictionaries:
immersion objective — n OIL IMMERSION LENS * * * a microscope objective designed to have its tip and the cover glass over the specimen connected by a liquid instead of by air. The liquid may be water (water immersion) or a specially prepared oil (oil immersion) … Medical dictionary
water immersion — the covering of the microscopical objective and the object with water … Medical dictionary
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immersion lens — noun or immersion objective : an objective of short focal distance designed to work with a drop of liquid (as oil or water) between front lens and cover glass * * * immersion lens noun A microscope object glass that works with a drop of oil or… … Useful english dictionary
Oil immersion — Principle of immersion microscopy. Path of rays with immersion medium (yellow) (left half) and without (right half). Rays (black) coming from the object (red) at a certain angle and going through the coverslip (orange, as the slide at the bottom) … Wikipedia
Immersion — can refer to:* Baptism by immersion * Immersion lithography or immersion microscopy, optical techniques in which liquid is between the objective and image plane in order to raise numerical aperture. * Language immersion * Immersion (mathematics) … Wikipedia
Immersion — Im*mer sion, n. [L. immersio; cf. F. immersion.] 1. The act of immersing, or the state of being immersed; a sinking within a fluid; a dipping; as, the immersion of Achilles in the Styx. [1913 Webster] 2. Submersion in water for the purpose of… … The Collaborative International Dictionary of English
Immersion lens — Immersion Im*mer sion, n. [L. immersio; cf. F. immersion.] 1. The act of immersing, or the state of being immersed; a sinking within a fluid; a dipping; as, the immersion of Achilles in the Styx. [1913 Webster] 2. Submersion in water for the… … The Collaborative International Dictionary of English
Objective — In a microscope, the objective (also called the objective lens) is the lens nearest to the object being examined whereas the lens closest to the eye is termed the ocular (the eyepiece). The light microscope today is usually binocular (with one… … Medical dictionary
immersion — 1. The placing of a body under water or other liquid. 2. In microscopy, filling the space between the objective lens and the top of the cover glass with a fluid, such as water or oil, to reduce … Medical dictionary
