Optical microscope red objective lens magnification
The red objective of an optical microscope represents a magnification of 4 times, yellow represents 10 times, blue represents 40 times, and white represents 100 times. Multiplying the eyepiece magnification by the objective magnification yields the total magnification of the microscope.
The "10" and "4" in the ascending digits of an optical microscope indicate that the magnification of the objective lens is 10 or 4 times. Here, the magnification is not the magnification of the area, but the magnification of the length or width of the image. The total magnification of the microscope is equal to the product of the magnification of the objective lens and eyepiece, and the magnification of the objective lens is proportional to its length. The larger the magnification of the objective lens, the longer the objective lens.
Parameter relationship of optical microscope
The working distance of the objective lens of an optical microscope is related to its focal length. The longer the focal length of the objective lens and the lower the magnification, the longer its working distance. Example: The 10x objective lens is marked with 10/0.25 and 160/0.17, where 10 is the magnification of the objective lens. 0.25 is the numerical aperture; 160 is the length of the lens barrel (in millimeters); 0.17 is the standard thickness of cover glass (in millimeters).
The effective working distance of a 10x objective lens is 6.5mm, and the effective working distance of a 40x objective lens is 0.48mm. The function of the objective lens is to magnify the specimen for the first time, and it is the most important component that determines the resolution of the microscope performance.
When the objective lens has already distinguished fine structures, if they have not been magnified by the eyepiece and cannot reach the size that the human eye can distinguish, then they cannot be seen clearly; However, fine structures that cannot be distinguished by the objective lens cannot be seen clearly even after being magnified by a high-power eyepiece. Therefore, the eyepiece can only serve as a magnifying lens and will not improve the resolution of the microscope.
