Objective lens microscopefunction

Air Duster, also called “canned air”, “compressed air”, and “dusting gas”, is used to provide a pressurized blast, knocking loose dust and dirt. Think of it as a portable replacement for an air compressor line. This accessory can be used to blow cookie crumbs out from a keyboard, clear out computer vents, and even open up tight apertures in an SMT (surface mount technology) stencil in PCB assembly. It’s one of those products that seems simple, but leads people to many misconceptions. In this article, we’ll cover the most common questions and misconceptions about duster. If we missed your specific question, please leave us a comment below or contact us and we'll get it answered.

To achieve the optimum force from a can of duster, spray a short three to five-second blast at room temperature. When an aerosol duster is sprayed continuously, it acts as an efficient heat sink and will cool down. This lowering of the can temperature also lowers the internal pressure of the can, which will greatly decrease the generated force.

What isobjective lensinmicroscope

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Parfocal: the objective lenses are mounted on the microscope so that they can be interchanged without having to appreciably vary the focus.

Total magnification: In a compound microscope the total magnification is the product of the objective and ocular lenses (see figure below).  The magnification of the ocular lenses on your scope is 10X.

Types ofobjectivelenses

Compoundmicroscope objective lens magnification

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High powerobjective microscopefunction

There is a misconception based on old information that dusters hurt the ozone layer. Dusters contained CFC’s over 20-years ago, but have since been replaced with materials that do not impact the ozone layer.

One way to change the refractive index is by staining the specimen.  Another is to use immersion oil.  While we want light to refract differently between the specimen and the medium, we do not want to lose any light rays, as this would decrease the resolution of the image.  By placing immersion oil between the glass slide and the oil immersion lens (100X), the light rays at the highest magnification can be retained.  Immersion oil has the same refractive index as glass so the oil becomes part of the optics of the microscope.  Without the oil the light rays are refracted as they enter the air between the slide and the lens and the objective lens would have to be increased in diameter in order to capture them.  Using oil has the same effect as increasing the objective diameter therefore improving the resolving power of the lens.

Customers looking for the lowest price often look to consumer retailers. Consumer duster is designed to be as cheap as possible, sometimes imported from outside the US. However, it isn’t designed for industrial use and may raise concerns:

Low powerobjective lens

High powerobjective lens

As the above details demonstrate, care needs to be taken even when choosing an everyday consumable like a duster. Reach out to us or your distributor for help deciding which duster is right for your application.

Most aerosol duster contains a refrigerant/propellant that cannot be considered “air”. As a matter of fact, inhaling too many of these vapors can lead to negative health effects. Compressed Air Duster is most commonly filled with the following propellants:

Immersion Oil:  Clear, finely detailed images are achieved by contrasting the specimen with their medium.  Changing the refractive index of the specimens from their medium attains this contrast.  The refractive index is a measure of the relative velocity at which light passes through a material.  When light rays pass through the two materials (specimen and medium) that have different refractive indices, the rays change direction from a straight path by bending (refracting) at the boundary between the specimen and the medium.  Thus, this increases the image’s contrast between the specimen and the medium.

Resolving power or resolution: the ability to distinguish objects that are close together.  The better the resolving power of the microscope, the closer together two objects can be and still be seen as separate.