The objective lens is the most important optical component of the microscope. Using light to make the object to be imaged for the first time, the direct relationship and the quality of the image and the optical parameters are the primary criteria for measuring the quality of a microscope. Qijiao is in the microscopic examination. When observing the image with a certain magnification objective lens, the image should be basically clear when converting the objective lens of another magnification, and the center deviation of the image should also be within a certain range. , that is, the degree of closing. The pros and cons of the parfocal performance and the degree of the axis are an important indicator of the quality of the microscope. It is related to the quality of the objective itself and the accuracy of the objective lens converter. First, the type of objective There are many types of objective lenses, which can be classified from different angles and are now classified. According to the degree of objective lens phase difference correction, it can be divided into: (1) Achromatic objective This is a common objective lens, often with the word "Ach" on the outer casing. This type of objective lens can only correct the positional chromatic aberration (red, blue and blue) and spherical aberration (yellow-green light) of the points on the axis and eliminate the collateral difference of the paraxial point. The chromatic aberration and spherical aberration of other colored lights cannot be corrected, and the field curvature is large. (2) Apochromatic objective The structure of the apochromic objective lens is complicated. The lens is made of special glass or fluorite. The outer lens of the objective lens is marked with the word "Apo". This objective lens can not only correct the color difference of the red, green and blue light, but also correct it. The difference between the red and blue dichromatic lights. Due to the perfect correction of various phase differences, the achromatic objective lens has a larger numerical aperture than the response magnification, which not only has high resolution, but also has excellent image quality and higher effective magnification. Therefore, the apochromatic objective lens has high performance and is suitable for advanced research microscopy and photomicrography. (III) Semi apochromatic objedtive The semi-apochromatic objective lens, also known as the fluorspar objective lens, the objective lens, is marked with the word "FL" on the outer casing of the objective lens. The number of lenses on the structure is larger than that of the achromatic objective lens, less than the negative achromatic objective lens, and the image quality is much higher. The achromatic objective lens is good, close to the apochromatic objective lens. The flat field objective lens is a thick lens that adds a fast half moon shape to the lens system of the objective lens to achieve the defect of correcting curvature of field. The flat field objective has a flat field of view and is more suitable for microscopic examination and microscopic photography. (4) Special objective lens The so-called "special objective lens" is designed and manufactured on the basis of the above objective lens to achieve certain specific observation effects. There are mainly the following: 1. Correction collar objective (Correction collar objective): A ring-mounted adjusting ring is arranged in the middle of the objective lens, and when the adjusting ring is rotated, the distance between the lens groups in the objective lens can be adjusted, thereby correcting the difference in coverage 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 outer casing of the objective lens, indicating that the error of the cover slip can be corrected from 0.11-0.23 mm thickness. 2. Iris diaphragm objective with iridescent aperture: The upper part of the objective lens barrel is equipped with an iridescent aperture, and the outer side can also be rotated by an adjustment ring. When rotating, the size of the diaphragm aperture can be adjusted. The objective lens of this structure is a high-grade oil immersion objective lens, and its function is dark. In the field of field microscopy, the illumination light is often entered into the objective lens for some reason, so that the background of the field of view is not dark enough, resulting in a decrease in the quality of the microscopic examination. At this time, the size of the aperture is adjusted, the background is blackened, the object to be inspected is brighter, and the microscopic examination effect is enhanced. 3. Phase contrast objective: This objective lens is a special objective lens for phase contrast microscopy, which is characterized by a phase plate at the back focal plane of the objective lens. 4, No cover objective (No cover objective): Some objects to be inspected, such as smearing, etc., can not be used on the cover glass, so the mirror should be used when the mirror is not used, otherwise the image quality will be significantly reduced, especially It is more obvious at high magnification. The housing of this objective lens is often marked with NC, while there is no 0.17 in the position of the thickness of the cover glass, and "0" is marked. 5. Long working distance objective lens: This objective lens is a special objective lens for inverted microscopes. It is designed to meet the microscopic examination of tissue culture, suspension and other materials. Pneumatic Valve,Clamped Butterfly Valve,Pneumatic Clamped Butterfly Valve,Electro Pneumatic Reversing Valve Wenzhou Gaoya Light Industry Machinery Co.,ltd. , https://www.hongyafitting.com
The objective lens has a complicated structure and is precisely fabricated. Due to the correction of the object difference, the metal objective lens barrel is assembled by a lens group which is separated by a certain distance and fixed. There are many specific requirements for the objective lens, such as the shaft and the parfocal.