Why is the resolution of optical microscopy highest when using an oil immersion lens?
Oil mirror, one of the optical microscopes, is used when the lens is immersed in oil (usually cedar oil) to observe finer structures. It is one of the commonly used microscopes in the laboratory, with slightly higher clarity than ordinary optical microscopes, used to observe chlamydia, bacteria, organelles, etc
The lens of the oil lens is very small. When light passes through the air between the glass slide and the oil lens, it undergoes refraction or total reflection due to different medium densities, reducing the amount of light entering the lens and making the object image unclear If cedarwood oil (n=1.515) with a refractive index similar to that of glass (n=1.52) is added between the oil mirror and the glass slide, it will increase the amount of light entering the lens, enhance the brightness of the field of view, and make the object image bright and clear
Due to the small size of bacteria, it is often necessary to use a microscope and oil microscope for clear observation in the study of bacterial morphology Therefore, it is necessary to proficiently master the use and protection methods of oil mirrors.
What should be noted when using an oil microscope for observation under a microscope
Before using the oil mirror, it is necessary to observe through low and high magnification mirrors, and then move the part that needs to be further magnified to the center of the field of view.
Raise the collector to its highest position and open the aperture to its maximum.
Rotate the converter to remove the high-power lens from the light hole, add a drop of tar onto the glass slide to be observed, and then slowly rotate the oil mirror. When converting the oil mirror, horizontally observe the distance between the lens and the glass slide from the side, so that the lens is immersed in the oil without crushing the glass slide.
Observe the eyepiece with your left eye and slowly rotate the fine adjuster until the image is clear.
If there is no object or the target is not ideal, when searching outside the refueling area, follow the procedure of low magnification → high magnification → fuel mirror. When searching in the refueling area, follow the procedure of low magnification → oil mirror, and do not use a high magnification mirror to avoid oil contaminating the lens.
After using the oil lens, first wipe it with lens cleaning paper, then use a small amount of xylene dipped lens cleaning paper to remove the cedarwood oil on the lens and specimen, and finally use dry lens cleaning paper to wipe it clean.
