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What is the principle and function of an aperture?

Release Date:

2021-06-02 13:27

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What is the principle and function of an aperture?

　　A light‑blocking ring serves to prevent stray light; for example, it’s used in smartphone lenses and camera lens assemblies. It’s formed by stamping SOMA light‑blocking material and is embedded as a Mylar sheet within the lens. Because of its light‑blocking function, it’s commonly referred to as a light‑blocking ring or a light‑blocking shim.

　　Its operating principle is based on the physical phenomenon of pinhole imaging, and its manufacturing requirements are quite stringent. Consequently, it places high demands on the materials used; in the market, Japanese SOMA light‑blocking material is predominantly employed—a double‑matte black PET film.

　　The aperture diaphragm on the condenser comes in various sizes; rotating it allows you to adjust the light intensity—larger apertures admit more light, brightening the field of view, while smaller apertures let in less light, dimming it. Turning the focusing knob adjusts the height of the microscope tube.

　　The primary function of a lens hood is

　　1: In the microscope’s structure, it is the coarse focus knob that adjusts the movement of the objective turret up and down, not the diaphragm; therefore, this option does not match the question.

　　2: During microscope operation, adjusting the fine focus knob can make the image clearer; therefore, this option does not match the question’s intent.

　　3: During microscope operation, adjusting the condenser mirror allows light to be reflected into the light‑path aperture. When illumination is weak, an concave mirror is used; when illumination is strong, a plane mirror is employed. Therefore, this option does not match the question’s requirements.

　　4: In the microscope’s structure, adjusting the size of the diaphragm aperture allows you to control the intensity of the light; during illumination, rotate the diaphragm so that the larger aperture aligns with the condenser opening—otherwise, if the aperture is too small, the field of view will appear dark. Therefore, this option is consistent with the question’s intent.

What is an aperture?

What about the light-blocking Mylar sheet?

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