Why does an optical microscope have the highest resolution 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 are the differences in usage between oil lenses and ordinary objective lenses
When using an oil lens, a drop of tar needs to be dropped on the glass slide, and the objective lens cannot detach from the oil drop during the ascent process. Moreover, the magnification of the oil lens is larger than that of a regular objective lens.
When using oil mirrors, attention should be paid to:
1. After using the oil lens, first use a lens cleaning paper dipped in a small amount of xylene to wipe off the cedar oil on the lens and specimen, and then use dry lens cleaning paper to clean them. After adding tar, the field of view noticeably darkens. It is necessary to raise the light collector to the highest position and open the aperture to the maximum. Before using the oil mirror, the target observed by the low-power and high-power lenses must be in the center of the field of view.
2. Cypress oil is a specialized oil for oil mirrors. Dropping a liquid with a refractive index of 1.5 under a 100x oil mirror can significantly increase the resolution of the oil mirror and improve the observation effect of the microscope. Cypress oil has a refractive index of 1.52, making it an excellent oil for microscope oil mirrors.
3. When using a microscope oil mirror, the microscope must be upright on the table, and the mirror arm must not be bent, causing the stage to tilt, in order to avoid the overflow of asphalt, affecting observation, and contaminating the table.
