Oil immersion

What is immersion oil used for?

Immersion oil is generally used to increase the resolution of a microscope by immersing the objective lens and specimen in a clear, high refractive index oil.

Why use immersion oil for immersion purposes?

• The highest magnification objectives have a very small focal length and the first lens of the objective is also small in diameter.
• The rays from the sample to the objective pass through the glass of the coverslip and, when they pass into the air, they separate from the normal. Some rays even suffer total reflection at the glass-air interface.
• Only a small portion of the light from the sample reaches the microscope, which can cause problems for vision.
• By placing a drop of cedar oil, with a refractive index almost equal to that of glass, between the objective and the cover glass, the emerging rays no longer deviate from the normal, but continue their path without deviation, thus ensuring that a greater amount of light reaches the objective, significantly improving vision.

How to use immersion oil?