ÖlImmersionsobjektiv

An Ölimmersionsobjektiv, often translated as oil immersion objective, is a specialized type of objective lens used in microscopy. Its primary function is to increase the resolving power of the microscope. This is achieved by immersing the front element of the objective lens and the specimen slide in a drop of immersion oil. Immersion oil has a refractive index that is very close to that of glass, typically around 1.515.

Light passing from the specimen through the glass slide and into the air would normally refract, or bend, significantly at the air-glass interface. This bending of light limits the amount of detail that can be resolved. By introducing a medium with a similar refractive index to glass, the refractive index difference at the interface is minimized, reducing the amount of light lost due to refraction.

This reduction in light scattering allows more diffracted light rays, which carry the fine details of the specimen, to enter the objective lens. Consequently, the numerical aperture (NA) of the objective, a measure of its light-gathering and resolving capabilities, is effectively increased. Higher NA values lead to better resolution, meaning the ability to distinguish between two closely spaced objects.

Ölimmersionsobjektivs are commonly used in fields such as microbiology and histology where high magnification and resolution are crucial for observing fine cellular structures, bacteria, or other small biological entities. They are typically used at magnifications of 100x and are found on higher-end light microscopes.