Among the huge variety of modern microscopes, it is very difficult to choose the one that best meets the needs of your laboratory.
When choosing a microscope, it is very important to pay attention to the lenses, because it is one of the most important elements of the optical system, which determines the magnification, clarity, image quality and cost of the microscope.
Below you can see the most important parameters of the lenses that you should pay attention to:
1. The lens of the microscope is characterized by a nominal magnification (usually from the range of 2.5; 3.2; 4; 5; 10; 20; 40; 63; 100; 120). The fraction of the magnification indicates the numerical aperture - the characteristic of the lens resolution and the maximum resolution of the lens in microns, the greater the value of the aperture - the better the resolution of the microscope, the smaller the details it can display.
The preferred lenses have an aperture of 1.4 and a maximum resolution of 0.12 μm.
2. Correction of the lens to the length of the microscope tube.
It is almost always 160-170 mm (DIN and JIS).
ü DIN standard - Deutsches Institut fur Normung (German Institute for Standardization) - designed to work with microscopes with a tube length of 160 mm and a parfocal height of 45 mm, they provide a greater working distance and are more often used in laboratory practice;
ü Standard JIS - Japan Industrial Standards (Japanese Industrial Standards) are designed to work with microscopes with a tube length of 170 mm and a parfocal height of 36 mm.
ü In addition, many modern microscopes today are equipped with infinity-corrected lenses - Infinity Corrected. Such lenses allow you to install additional optical elements without disturbing the image, which will be especially useful for fluorescent, polarizing, phase-contrast microscopes and others.
Typically, microscope manufacturers use their patented designs and have their own unique Infinity Corrected lens standards, so it is recommended that you buy lenses from the same brand as your microscope.
3. For biological microscopes indicate the presence of correction for the thickness of the cover glass of the drug in mm. It is almost always 0.17 or no correction (0 or -). Occasionally there are lenses for inverted microscopes (ie for microscopes in which the observation is made from below, through a glass slide, Petri dish, flask glass, etc.) with compensation of 1.2.
4. The light transmitted through the lens generates color aberration (distortion), which has a different refractive index according to the wavelength. The lenses are divided according to the type of correction of these aberrations and have their own letter designations:
· Aberration-corrected lenses with two primary colors are called achromats (ACHRO, usually unlabeled)
· Lenses with aberration correction in three colors - apochromats (marked with the letters APO or consonant)
5. After the light passes through the lens, there are uneven focusing on the field of view (curvature of the field of view):
· Adjusted lenses with a flat field of view in which the aberration of the field curvature is corrected in such a way that focuses not only the center of the lens but also the periphery are indicated by the prefix Plan- to indicate color correction, such as planachromats or planapochromat. The lens with this correction contains the words Plan, Plan, Pl or consonant. These lenses are more expensive and give a better and clearer image across the field of view.
· Lenses with incomplete correction can be marked as Pivlan-Semi plan, S-Plan or the manufacturer's own designation. These lenses are cheaper, but have uneven focusing.
6. To improve the brightness and numerical aperture, the space between the lens of the lens and the object of observation is filled with a transparent liquid with the required refractive index. Such lenses are called immersion. This is usually done for lenses with a magnification of 40 and above. As a liquid most often use a special synthetic oil (lens labeled Oil), less water (W) or glycerin (Gli).
7. Lenses for luminescent studies are made of materials with minimal intrinsic luminescence and good ultraviolet transmission, because most ultraviolet illumination is carried out by the lens (in fluorescent microscopes). The lens performs the functions of a condenser. Lenses for fluorescent studies are labeled FLUOR.
Given the wide variety of possibilities of using a microscope, choose it for the needs of your laboratory.
The Dutch company Euromex, which has been developing and manufacturing its own optical devices and microscopes for more than 40 years, will help you choose the right microscope.
Euromex is the best choice for those who choose European quality at a reasonable price! A wide selection of models for every taste and for any laboratory, for individual needs!
