The magnification is also an important parameter of the microscope, but we can't blindly believe that the higher the magnification, the better. When selecting, we should first consider the numerical aperture 。 There are two kinds of magnification Spherical reflector When imaging, the ratio of image height to original object height is called linear magnification (applicable to cameras Projector And other optical instruments); Using visual aid optical instruments Observe objects When, like Eye contact The ratio between the angle of view (i.e., the angle of view) and the angle of view when observing objects directly with the eyes is called Angular magnification 。 The angular magnification of the telescope is equal to the focal length of the objective lens and eyepiece The ratio of focal length. Convex lens be used as magnifier Angular magnification at Approximately equal to Photopic distance (about 25cm) to focus. For example, a magnifying glass has a focal length of 10cm, and its angular magnification is 2.5 times, usually writing 2.5x. The angular magnification of the microscope is equal to the product of the linear magnification of the objective lens and the angular magnification of the eyepiece. 40x (objective linear magnification), l0x (eyepiece angular magnification) and other words are engraved on the objective lens and eyepiece of the microscope respectively. The combination of objective lens and eyepiece with different multiples can make the microscope obtain different angular magnification. y'/y=(f/s)2=s'/s
Y height
F Focal length
From this formula, ss'=f2 [1]
Convex lens imaging Magnification formula: Magnification=h '/H=v/u. Where h' is image height, H is object height, v is image distance, and u is object distance According to the above formula, the image magnification can be calculated from the known image distance and object distance
