How to calculate the field of view under a microscope
Reading pathological films 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 to observe and record the results of film reading is scientific. As is well known, the imaging of a microscope is first magnified and imaged by the objective lens on the specimen, and then magnified by the eyepiece and observed by the naked eye. The size of the field of view that can present an image is determined by the number of fields of view of the eyepiece. It should be noted that the observations and records described in this article are observed and recorded through a microscope with an eyepiece. Other optical paths that are not observed by the eyepiece are used to capture and record images, such as CCD, digital cameras, and images captured through software operation. The field number (FN) of a microscope eyepiece is different, and the size of the field of view that can be seen under the microscope is different. Different area areas have an impact on the positive rate count under the microscope. We should understand the relationship between the number of eyepiece views and the field of view area. A small field of view results in a smaller visible field of view area, while a large field of view results in a larger visible field of view area.
Identification of the number of fields of view for an eyepiece
The design and production of microscopes have international standards, and the field of view is indicated on the eyepiece of the microscope, such as the Olympus BX50 microscope, which has a field of view of 22 (the English and numerical symbols before the 22 value are the eyepiece classification name and magnification).
2 Actual field of view and calculation formula
The area (circular area) that can be observed by a microscope on the specimen plane 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 for pathological counting refers to 40.
4 intermediate magnification
Observing directly through the eyepiece without considering intermediate magnification. Intermediate magnification refers to the magnification of the CCD interface, photographic eyepiece, and CCD components added to the optical path. Because most of the microscopes currently used are infinite imaging systems with additional features such as fluorescence observation, intrinsic difference observation, differential interference observation, etc., the components do not change magnification and do not need to be considered.
Field of view under 5 commonly used eyepieces
The most commonly used eyepiece field of view for zu is 22. Various microscope manufacturers have successively designed and produced wide field of view 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 values of 18 and 20.
