Microscope Maintenance

Customers often ask what they can do when they have problems with lubrication and focusing problems with their microscopes. Here are a few questions along with our suggestions:
Question: What product should I use to lubricate the bearings on the stage of the microscope?
Answer: Each manufacture has their own line of lubricants they recommend. If you bought everyone for each product it would be extremely expensive. We use a product called Super Lube made by Permatex. It should be available from many stores in your area. We use this product on all brands of microscopes that we service.
Question: My stage seems to slip down out of focus for no reason. What can I do to prevent this?
Answer: There are two main reasons for this problem. Either the tension control is too loose, or the main bearing system in the stage mechanics needs some adjustments.
You, as the microscope user, can adjust the tension control. Many microscopes have focus tension controls attached next to the coarse focus control. This control may be the simple type that you can adjust by just using your hand, or it may take a special tool. On Olympus or Nikon microscopes the adjustment is usually on the right side of the scope as the stage faces the user. It is a thin control knob or disc that is placed between the microscope stand and the coarse focus control. All you have to do is turn this device one way or the other and it will increase or decrease the tension on the coarse focus control knob. This in turn will keep the stage from slipping down. Make sure you are not turning the stage lock control, which is normally on the opposite side of the tension controller. If your microscope takes a special tool to adjust the tension. and you have lost this tool, you will need to contact the microscope manufacture or the company you purchased your microscope from and request the adjustment tool.
If the main bearing system needs adjustment you will should contact a qualified microscope repair technician to do this repair.

Microscope Maintenance

Microscope Immersion oil

As magnification increases on a microscope the correction in refractive index is a requirement for finer resolution and brightness. As the light cone passes through the different layers of glass, sample mounting media and air light tends to bend at different angles. In most cases the sequence of the light leaving the substage condenser is glass (1.515nD), air (1.00nD), glass slide (1.515nD), sample, mounting media, cover slip (1.515nD), into the objective lens which is approximately 1.515nD.

Immersion oil has a refractive index of 1.515nD and is applied to the top of the cover slip and then the tip of the oil immersion objective is then immersed into the drop of oil. This completes the “optical connection”.

The resolution obtained is directly related to the angular aperture (AA), the larger the A.A. having a wider cone with more scattered (oblique) rays. Unless there is a homogenous light path, the most oblique rays are lost to internal reflection inside the glass slide or cover slip. The use of immersion oil permits full use of the resolving power of the objective lens. Immersion oil objectives increase the resolution by approximately fifty percent over dry objectives of equivalent focal length.

The resolving power of an optical system is figured by averaging the numerical aperture (N.A.) value of the objective and the working N.A. of the condenser.

The acid value of immersion oil should be very low. If not then the higher acid content can lead to eventual deterioration of the metal parts of the objective lens or worse yet the dissolving of the cements used to manufacture the lens. This is turn leads to a leakage problem as immersion oil is wicked up into the interior of the lens.

Viscosity of the oil is up to the user. Lower viscosities tend to run and spread all over the microscopes requiring more clean up. Higher viscosities are more practical and not as messy. Very high viscosities are used for instruments that are mounted on slight angles.

When applying immersion oil use only the amount required for the individual slide. Too much oil does not help with the optical performance as much as it requires more clean up. Not enough oil will not allow a good optical contact with the objective.

Which oil is the best? Our choice is Cargille Immersion Oil. It is manufactured with the best materials. Immersion oil must meet the design requirements of older microscopes and become the design criteria for new instruments.

Author Name: Rowland Brasch: Nationalmicroscope.com

Microscope Immersion oil

ATAGO PRM-100a In-Line Refractometer

The successful series of In-line digital refractometers by Atago Company LTD has added a new product, and it is being carried by National Microscope Exchange. The newly released ATAGO PRM-100a digital refractometer has replaced the popular older style PRM-85 and PRM-85SE instruments, which were a mainstay of the company for years. Atago Company is one of the most respected world leaders in manufacture of refractometer products according to National Microscope Exchange President Rowland Brasch.

“The newly designed PRM-100a In-Line refractometer continues on in the tradition of excellent ATAGO products which have made it a world leader in refractometry,” said Brasch. “The new ATAGO-PRM-100a incorporates the accuracy and ease of use found in the less expensive model CM-780N, but adds the features of a higher degree of accuracy along with the capability to measure refractive index as well as brix.”

The new PRM-100a In-Line refractometer has accuracy readings of +/- 0.05% brix and +/- .00010 for refractive index, and has two options for setting the minimum indication decimal place, as well as the ability to set a User-Defined Scale (input via RS-232C). This instrument is easily connected to your system by attaching the unit to a piping system to monitor food or beverage production, pharmaceutical production, industrial fluid, washing devices, dilution/mixing devices, etc. The in-line refractometer will continuously monitor water content and mixing ratio with successive measurements of refractive index, Brix, or concentration.

“ATAGO refractometers such at the PRM-100a are popular with users because of their accuracy and ease of use,” said Brasch. “The PRM-100a In-Line refractometer is more accurate than other ATAGO In-Line refractometers, making it more attractive to users.”

You can learn more about National Microscope Exchange products by visiting www.nationalmicroscope.com or by calling 800-851-7635.

Author Name: Rowland Brasch: Nationalmicroscope.com

ATAGO PRM-100a In-Line Refractometer