Geologist’s Guide to Olympus BX50 Polarizing Microscope
Read the Edited Video Transcript for ‘Geologist’s Guide to Olympus BX50 Polarizing Microscope’
Hey, this is Chad with Munday Scientific and Microscope Marketplace. Today we’re going to take a look at an Olympus BX50 polarizing microscope.
We recently sold this microscope, and it’s being shipped out to New Mexico. In this video, we’ll go over how to disassemble and reassemble the microscope, and we’ll also highlight several features that will help the end user get the most out of it.
As usual, Michael is going to join in and help demonstrate some of the steps.
The Essential Tool: 3 mm Allen Wrench
On Olympus BX microscopes, one of the most important tools you’ll use is a 3 mm Allen wrench. This tool works for nearly every adjustment and removal point on the microscope, with only one exception that we’ll cover later.
It’s extremely handy and used for tasks like:
- Removing the camera adapter
- Detaching the viewing head
- Removing the nosepiece
- Taking off accessories like the stage holder
Trinocular Viewing Head and Light Path Control
This microscope is equipped with a trinocular viewing head, which allows you to attach a camera for imaging.
There is a light path selector rod located on the head:
- All the way in: 100% of the light goes to the eyepieces
- Middle position: Light is split between the eyepieces and the camera
- All the way out: 100% of the light goes to the camera
This allows users to either observe through the eyepieces, capture images through the camera, or do both simultaneously.
Camera Adapter and Focus Adjustment
The microscope includes an Optium camera adapter.
To remove the camera adapter, loosen the 3 mm Allen screw and lift it off the trinocular port.
This adapter is a 0.5× reduction lens, which is important because the image seen through the eyepieces may not perfectly match what appears on the camera.
To correct this:
- Focus the specimen through the eyepieces first.
- With the camera attached, use the adjustment wheel on the adapter.
- Rotate the wheel while watching the camera display to bring the image into focus.
This ensures the camera image matches the eyepiece focus.
Eyepieces and Crosshair Adjustment
The microscope includes two eyepieces:
- One fixed eyepiece
- One focusable eyepiece
There is also a diopter adjustment tube that allows the fixed eyepiece to be focused.
For initial setup, align the zero marking on the eyepiece with the white reference dot. This provides a good starting point for users with normal vision.
Because this is a polarizing microscope, one eyepiece contains a crosshair reticle. The focusable eyepiece allows users to bring the crosshair into sharp focus by rotating it.
The reticle assembly includes a small positioning pin and slot, which allows the reticle to be rotated easily with one hand.
Bertrand Lens and Analyzer
This microscope includes a Bertrand lens, which is used for observing interference patterns in polarizing microscopy.
The Bertrand lens assembly includes:
- A rotating analyzer (180° rotation)
- A pull-in/pull-out analyzer control
- A slot for wave plates
For this microscope, the customer requested a TP530 nm wave plate, which is already installed.
Once installed and centered, the user simply needs to center the stage at the 10× objective, and the microscope will be ready to use.
Centerable Nosepiece and Objectives
This microscope uses a centerable nosepiece, which allows each objective to be individually aligned for polarizing work.
Always lower the stage before removing the nosepiece.
The objective configuration for this microscope includes:
- 4× objective
- 10× objective
- 20× objective
- 40× objective
Each objective can be centered using adjustment screws, but we have already pre-centered the objectives to make setup easier for the customer.
Condenser and Polarizer
Next, we move to the condenser assembly.
To remove the condenser:
- Raise the stage.
- Lower the condenser using the two condenser adjustment knobs.
- Loosen the knurled thumb screw and remove the condenser.
This microscope uses a U-PC2 flip-top condenser.
Key features include:
- Integrated polarizer
- Aperture diaphragm for contrast control
- Flip-top lens element for low magnification objectives
When using most objectives, the top lens element should remain in place for optimal image quality. If a 2× objectiveis used, the top lens can be flipped out.
When reinstalling the condenser, align the guide pin with the slot in the microscope frame. Insert the condenser slightly at an angle and rotate it until it slides fully into place.
Illumination Filters and Field Diaphragm
The microscope also includes several built-in illumination controls.
These include:
- Field diaphragm
- Daylight blue filter (LBD)
- Neutral density filters (ND6 and ND25)
The daylight blue filter helps simulate natural daylight color temperature, while neutral density filters reduce light intensity without affecting color balance.
These filters can be flipped in or out depending on imaging needs.
Slide Holder and Stage Adjustment
The microscope includes a U-FMP slide holder, which allows the stage to move the specimen in both directions.
If you prefer not to use the slide holder, it can be removed using the 3 mm Allen screw located in the center.
The stage can also be re-centered using the two adjustment screws located on the stage.
The stage also includes a click-stop rotation mechanism, which allows users to lock the stage into defined rotational positions.
Reassembling the Microscope
Once the components have been inspected or transported, the microscope can be reassembled:
- Lower the stage.
- Reinstall the nosepiece.
- Reattach the slide holder.
- Mount the trinocular head and tighten it with the 3 mm Allen wrench.
If necessary, the objectives can be centered using a 1.5 mm Allen wrench.
Power Controls and Illumination Adjustment
The microscope includes a standard power switch and rheostat brightness control.
There is also a preset brightness button. If this button is activated, the brightness knob will no longer change the light intensity.
If that happens, you can adjust the preset level using a flathead screwdriver inserted into the adjustment port.
Changing the Bulb
Always unplug the microscope before replacing the bulb.
To change the bulb:
- Use the 3 mm Allen wrench to loosen the lamp housing screw.
- Remove the lamp housing.
- Loosen the screw on top of the housing.
- Slide the lamp housing open.
The microscope uses a 12V 100W halogen bulb.
To remove the bulb:
- Press down the two metal clips
- Lift the bulb out
When installing the new bulb:
- Do not touch the glass with your fingers
- Use the protective wrapper or a lint-free tissue
- Press the bulb into place and release the clips
Reassemble the lamp housing and reinstall it onto the microscope.
Application
This particular microscope will primarily be used for geology applications, where polarizing microscopes are commonly used to analyze mineral samples.
Contact Information
If you have any questions about this microscope or any other microscopes available through Microscope Marketplace and Munday Scientific, feel free to contact us.
Closing
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