Metallographic microscope special objective lens classification
Special objective lenses are specially designed and manufactured to achieve certain specific observation effects, mainly as follows:
1. Correctioncollar objective: There is a ring-mounted adjustment ring in the middle of the objective lens. When the adjustment ring is turned, the distance between the lens groups in the objective lens can be adjusted, thereby correcting the coverage difference caused by the non-standard thickness of the cover glass. The scale on the adjustment ring can be from 0.11--.023, and this number is also marked on the shell of the objective lens, indicating that the error between the thickness of the cover glass from 0.11-0.23mm can be corrected.
2. (Irisdiaphragmobjective: There is an iris diaphragm on the upper part of the objective lens barrel, and an adjustment ring that can also be rotated outside. When rotating, the aperture of the diaphragm can be adjusted. The objective lens of this structure is the best oil immersion objective lens. Its function is that in the dark field microscope inspection, the background of the field of view is not dark enough, resulting in a decline in the quality of the microscope inspection. At this time, adjust the size of the aperture to darken the background, make the object under inspection brighter, and enhance the microscope inspection effect.
3. Phasecontrastobjective: This objective lens is a special objective lens used for phase contrast microscopy, and its characteristic is that a phase plate is installed at the back focal plane of the objective lens.
4. Nocover objective: Some objects to be inspected cannot be covered with a cover glass. In this way, no cover objective lens should be used in the microscope inspection, otherwise the image quality will be significantly reduced, especially in high-magnification microscope inspection. The shell of this objective lens is often marked with NC, and there is no word 0.17 on the position of the thickness of the cover glass, but "0" is marked.
5. Long working distance objective lens: the focal length of this objective lens is larger than that of ordinary objective lens, and it is designed to meet the microscope inspection of liquid materials (high temperature metallography), liquid crystal, tissue culture, suspension and other materials.
