Nikon PLan Fluor ELWD objective lens 10/20x/40x/60x

Nikon PLan Fluor ELWD objective lens 10/20x/40x/60x

Nikon PLan Fluor ELWD objective lens 10/20x/40x/60x

Product Name: Nikon Microscope Long Working Distance Objective Lens
Product model: TU PLan ELWD 50X/0.6B

Numerical aperture: NA: 0.6

Working distance: 11mm

Optical path: Reflection at infinity

Nikon microscope objective TU PLan ELWD 50X/0.6

The objective lens is an important optical component of a microscope, which uses light to produce secondary images of the object being inspected. Therefore, it directly affects the quality of imaging and various optical technical parameters, and is the primary standard for measuring the quality of a microscope.

The structure of the objective lens is complex and the production is precise. Due to the correction of aberrations, it is composed of lens groups that are fixed at a certain distance inside a metal object tube. Each group of lenses is glued together with one to several lenses of different materials and parameters. The lens in front of the objective lens is calledThe "front lens" and the rear lens are called the "rear lens", and the total focal length of the objective compound lens group is the focal length of the objective lens. The distance between the front lens of the objective lens and the object being inspected is the working distance (free working distance). During high magnification inspection, in order to prevent the objective lens from coming into contact with the slide, crushing the glass slide, and damaging the lens, in addition to the spring device at the tip of the objective lens, the entire set of objective lenses must be aligned from low magnification to high magnification.

During mirror inspection, when observing a clear image with an objective lens of a certain magnification, the image should be basically clear when switching to another magnification lens, and the center deviation of the image should also be within a certain allowable range, that is, the degree of axis alignment. The quality of the microscope is determined by the quality of the objective lens itself and the accuracy of the objective converter, as well as the quality of the focusing performance and the degree of alignment. High quality microscopes are all coaxial and in focus.

There are many types of objective lenses that can be classified from different angles, which are now described separately.

According to the different media between the front lens of the objective lens and the cover glass, it can be divided into:

• Objective lens: During inspection, there is air between the front lens of the objective lens and the cover glass（or=1）For the medium. This type of objective lens is commonly used, such as40XThe numerical aperture values of the following objectives are all less than1.

• Immersion type objective lens: During mirror inspection, water is used between the front lens of the objective lens and the cover glass（or=1.333）For the medium. Water is distilled water, and this type of objective lens is currently rarely used.

• Oil immersed objective lens: also known as oil lens, with a magnification of90-100XDuring microscopic examination, tar or non fluorescent oil (η) is often used between the front lens of the objective lens and the cover glass=1.515Left and right are media. In addition, sometimes glycerol is also used（or=1.450）Paraffin wax（or=1.471）As a medium. The casing of this type of objective lens is often marked with“oil”、“IL”Or“HI”Words.

The media used for the above-mentioned water immersion and oil immersion objective lenses are both liquid substances, so they are also known asThe numerical aperture value of the immersion system objective lens can be greater than1.

The oil lens must be wiped immediately after use and cannot be left for a long time, otherwise it will damage the lens and reduce the resolution, and it is also difficult to wipe after being soaked in oil and dried up. Wiping is a process of lightly wiping off oil with a degreased cotton ball dipped in a small amount of sprinkled essence mixture, and then lightly wiping with a degreased cotton ball or lens paper.

According to the magnification of the objective lens, it can generally be divided into:

• Low magnification objective lens:1X-6X，NA0.04-0.15；

• Medium magnification objective lens:6X-25X，NA0.15-0.40；

• High magnification objective lens:25X-63X，NA0.35-0.95；

• Oil immersed objective lens:90X-100X; NA1.25-1.40.

Classifying based on the degree of aberration correction of the objective lens is a classification method that users should understand. It is now described as follows:

• Achromatic objective lens（Achromatic objective）This is a common objective lens, often found on the casing“AchThe words,

Its structure is relatively simple, consisting of two lenses glued together and two or more lenses.

This type of objective lens can only correct the positional chromatic aberration and spherical aberration of points on the axis, as well as eliminate the aberration of points near the axis. Due to raw materials such as glass

Due to the inability to correct chromatic aberration and spherical aberration of other colors, and the large field curvature, it cannot be applied to advanced research microscopy and microphotography. During mirror inspection, it is usually used in conjunction with Huygens eyepieces.

• Apochromatic objective lens（Apochromatic objective）The structure of the apochromatic objective lens is complex, and the lens adopts

Made of special glass or materials such as fluorite and fluorite, the outer shell of the objective lens is marked with“APO”Words. This type of objective lens can not only correct the chromatic aberration of red, green, and blue light, but also create images on the same focal plane, achieving the effect of eliminating "residual chromatic aberration" (also known as secondary spectrum). At the same time, it can effectively correct the spherical aberration of red and blue light. Due to its excellent correction of various aberrations, it has a larger numerical aperture than the corresponding magnification achromatic objective lens, which not only has high resolution and excellent image quality, but also has a higher effective magnification. Therefore, the performance of the compound achromatic objective lens is very high, suitable for advanced research microscopy and microphotography. When inspecting the mirror, it should be used in conjunction with a correction eyepiece, otherwise the image quality will deteriorate.

• Semi achromatic objective lens（Semi apochromatic objective）Half complex achromatic objective lens, also known as fluorite objective lens

The casing of the objective lens is often marked with“FL”Words. Structurally, the number of lenses is more than that of achromatic objectives and less than that of apochromatic objectives; In terms of imaging quality, it is much better than achromatic objectives, close to apochromatic objectives, and can correct the chromatic aberration and spherical aberration of red and blue colors. During mirror inspection, it should also be used in conjunction with a compensating eyepiece.

• Flat field objective lens（Plan objective）Flat field objective lens is a type of lens system that adds a thick half moon shaped lens

Lens to achieve correction of field curvature defects. The structure of flat field objectives is relatively complex, especially for high magnification flat field objectives. The field of view of a flat field objective lens is flat and large, And the working distance has also increased accordingly. Therefore, it is more suitable for use in microscopy and microphotography.

Flat field objective lenses include: flat field achromatic objective lenses, which are marked on the outer shell of the lensPlan AchThe flat field apochromatic objective lens is marked on the lens housingPlan APOAnd there are also flat field semi chromatic aberration reducing objectives, and more advanced ones are ultra flat field objectives and ultra flat field chromatic aberration reducing objectives.