What is immersion oil and why is it used

Light microscopy technique

In light microscopy, oil immersion is a technique used to increase the resolving power of a microscope.

Oil immersion lens 100x

What is the function of the immersion oil?

Oil immersion objective magnification

Types of immersion oil

Oil immersion objective microscope

This is achieved by immersing both the objective lens and the specimen in a transparent oil of high refractive index, thereby increasing the numerical aperture of the objective lens.

Without oil, light waves reflect off the slide specimen through the glass cover slip, through the air, and into the microscope lens (see the colored figure to the right).

Unless a wave comes out at a 90-degree angle, it bends when it hits a new substance, the amount of bend depending on the angle. This distorts the image.

Why do you use immersion oil with 100x objective lens

Air has a very different index of refraction from glass, making for a larger bend compared to oil, which has an index more similar to glass. Specially manufactured oil can have nearly exactly the same refractive index as glass, making an oil-immersed lens nearly as effective as having glass entirely around the sample (which would be impractical).

Immersion oils are transparent oils that have specific optical and viscosity cha

what is the use of oil immersion objective

at what objective is the oil immersion only be applied