Matthew Parry-Hill and Michael W. Back to Introduction to Microscope Objectives. Back to Microscope Objective Specifications. World-class Nikon objectives, including renowned CFI60 infinity optics, deliver brilliant images of breathtaking sharpness and clarity, from ultra-low to the highest magnifications.
Related Nikon Products Optics World-class Nikon objectives, including renowned CFI60 infinity optics, deliver brilliant images of breathtaking sharpness and clarity, from ultra-low to the highest magnifications. Objective Selector Filter, find, and compare microscope objective lenses with Nikon's Objective Selector tool. Share this tutorial:. Immersion Oil and Refractive Index Introduction. Get updates on our social media channels:. Numerical Aperture NA determines the limit of the Resolution that your microscope can achieve.
Briefly, NA is related to the capability of your lens to gather lights. The value of NA ranges from 0. The higher the NA, the better the Resolution is. When the light passes from a material of one to another for example: from glass to air , it bends due to the refractive index difference between two materials.
The light could be refracted or scattered and lost. Generally speaking, when using lower magnification objective lenses 4x or 10x the light refraction is not usually noticeable. However, once you use the 63x or higher objective lens, the light refraction when using a dry lens means without immersion oil is significant. If you can reduce the amount of light refraction, more light passing through the microscope slide will be directed through the very narrow diameter of a higher power objective lens.
In microscopy, more light is equal to a clearer and crisper image. By placing a medium, such as immersion oil with a refractive index equal to that of the glass slide, in the space filled with air, more light is directed through the objective and a clearer image is observed. The refractive index of air is 1, while the refractive index of immersion oil is 1.
Therefore, allowing all the light to pass to the lens. Below is an example. The images were captured using a microscope with a 63x objective lens. Most of the commercial immersion oils have refractive indexes of around 1.
This improves the resolution of your high-power immersion objective and increases your NA by lowering refraction. However, there is a physical limitation to how far you can go before the nose tip of the objective hits the coverslip. Go any further than this distance and you will not be popular! Cleaning glass shards out of a condenser is a time consuming and expensive business. Not to mention you can damage the objective front lens.
In general there is an inverse relationship between magnification and working distance. An objective with 10X magnification has an approximate working distance of 4 mm, whereas a X oil immersion objective has a working distance of approximately ? Cedar Wood oil was the immersion oil of choice for many years before the large scale manufacture of synthetic alternatives. And you can still buy Cedar Wood oil today. However, this oil can have many disadvantages. If not correctly cleaned up after use, it can penetrate and damage the cement which holds the objective front lens in place.
Modern synthetic oils are designed to remain colour stable over time as well as being relatively inert. If you are carrying out long-term, live-cell imaging experiments that require temperature controlled chambers around the cells and stage, then you need to choose your immersion oil carefully.
Most oils are designed to work at room temperature i.
0コメント