How to use the oil lens of a microscope
How to use the oil lens of a microscope:
When using an oil lens, when selecting an observation area with a low-magnification objective lens, people often underestimate the small object field of a high-magnification objective lens, so that they may focus on an empty field of view. At the same time, the center of the objective lens is rarely extremely accurate, so the field of view of a high-power objective lens cannot be accurately estimated. These bring great difficulties to the focusing of the oil lens. In this case, a very small piece of cigarette tin foil or a very thin piece of tin foil can be sealed together with the specimen under the cover glass, so that it is easy to use an oil lens to find a focusing plane that is very close to the specimen.
When using an oil lens, you can directly turn back to the low-magnification objective lens for observation without wiping off the immersion oil. The immersion oil layer will not have a great impact on the image formation when using a low-magnification objective lens, and the front lens of the objective lens will not come into contact with the immersion oil. At the same time, the immersion oil on the cover glass will not increase the image quality of the cover glass object. Influence.
The earliest immersion oil used in Olympus microscopes was fir oil with a refractive index of 1.512-1.518. This immersion oil increases in dryness when exposed to air and has slower polymerization properties. Many microscope manufacturers now offer a non-resinous synthetic immersion oil with a refractive index of 1.5 1 5-1.5 18 and suitable dispersion properties. Due to its good properties and suitability for high-quality oil immersion work, Now it has gradually replaced the above two resinous impregnated oils. Therefore, it is recommended to use this kind of lens oil when using oil lenses.
Just a drop of immersion oil is enough. Too much immersion oil is not only useless for observation, but also brings a lot of trouble to cleaning the oil lens after use. At the end of the observation, even if you use non-resinous immersion oil, you must carefully clean the objective lens and cover glass. First wipe off the immersion oil with dry lens paper or dry cloth, and then use a lens dipped in xylene or gasoline to remove the immersion oil. Wipe away any remaining oil with lens tissue or cloth.
The principle of oil lens:
The oil microscope is one of the commonly used microscopes in the laboratory. Its clarity is slightly higher than that of ordinary optical microscopes. It is used to observe finer structures such as chlamydia, bacteria, and cell organelles.
When using an oil lens, drop drops of cedar oil on the slide. This is because the magnification of the oil lens is high and the lens is very small. When light passes through media objects of different densities (glass slide → air → lens), part of the light will be refracted and lost. Less light will enter the lens barrel and the field of view will be smaller. Dark, objects cannot be seen clearly. If cedar oil (n=1.515), which is similar to the refractive index of glass (n=1.52), is dropped between the lens and the glass, the light entering the oil lens will increase, the brightness of the field of view will be enhanced, and the object image will be clear.
