How to calculate the area of the field of view of a microscope under a microscope
Performing pathological imaging under a microscope is one of the important tasks in the work of pathologists. The results observed and recorded under a microscope are the scientific basis for clinical diagnosis. The correct and standardized use of a microscope is necessary to observe and record the results of the image reading in order to have scientific validity. As is well known, the imaging of a microscope is first magnified and imaged by the objective lens, and then observed by the naked eye with a single magnification by the eyepiece. The size of the field of view that can be presented is determined by the number of fields of view of the eyepiece. It should be noted that the observation and recording described in this article are conducted through a microscope with an eyepiece. Other optical paths that are not observed through the eyepiece, such as CCD, digital cameras, and images captured by software operation, are described separately. The field number (FN) of the microscope eyepiece varies, and the size of the field of view that can be seen under the microscope also varies. Different area regions have an impact on the positive rate count under the microscope. We should understand the relationship between the field number of the eyepiece and the field of view area. The smaller the number of fields of view, the smaller the visible field of view area; conversely, the larger the number of fields of view, the larger the visible field of view area.
Identification of the number of fields of view for eyepiece 1
The production has international standards, and the field of view is marked on the eyepiece of the microscope, such as the Olympus BX50 microscope, which has a field of view of 22 (the English and numbers before the 22 value indicate the eyepiece classification name and magnification).
2 Actual field of view and calculation formula
The area that can be observed by a microscope on the specimen plane (circular area) is called the actual field of view, also known as the field of view. The area size can be calculated using the following formula.
3 objective magnification
Objective lens is an important optical component used for microscope imaging. The commonly used objective magnifications for biological microscopes are 4, 10, 20, 40, and 100. The commonly used high-power objective lens for pathological counting refers to 40.
4 Intermediate magnification
Directly observe through the eyepiece without considering intermediate magnification. Intermediate magnification refers to the magnification of CCD interfaces, photographic eyepieces, and CCD components added to the optical path. Because most microscopes currently used are infinite distance imaging systems with additional features such as fluorescence observation, aberration observation, differential interference observation, etc., the components do not change magnification and do not need to be considered.
Field of view area under 5 commonly used eyepieces
The most commonly used eyepiece field of view is 22. Various microscope manufacturers have successively designed and produced wide field eyepieces with a field of view of 25 and ultra wide field of view eyepieces with a field of view of 265. There are also eyepieces with smaller field of view numbers of 18 and 20.
