Olympus BX51 Fluorescence DIC Breakdown
Read the Edited Video Transcript for ‘Olympus BX51 Fluorescence DIC Breakdown’
Hey, this is Chad with Munday Scientific. Today, we’re going to take a look at this Olympus BX51 fluorescence and DIC microscope.
DIC stands for Differential Interference Contrast, also commonly referred to as Nomarski microscopy. This particular microscope has also been configured for fluorescence to meet the customer’s specific application requirements.
Let’s go through the system and take a closer look at how everything works.
Trinocular Head and Camera Light Path
The customer requested a trinocular head so they can capture fluorescence images with a camera.
The trinocular head has a pull rod on the side that controls how the microscope’s light is distributed between the eyepieces and camera.
There are three positions:
- All the way in: 100% of the light goes to the eyepieces.
- Middle position: 50% of the light goes to the eyepieces and 50% goes to the camera.
- All the way out: 100% of the light goes to the camera.
A diagram on the microscope head indicates the three positions.
Accessing the Fluorescence Filter Cubes
Next, let’s look at the fluorescence filter cubes.
To access the cubes, remove the microscope’s 3 mm Allen wrench and locate the retaining screw on the side of the fluorescence illuminator.
Loosen the screw and slide the filter cube assembly out.
This particular microscope is equipped with two fluorescence filter cubes.
Removing and Installing Filter Cubes
Each fluorescence cube is mounted on a dovetail.
To remove a cube, loosen its retaining screw and slide the cube out of the dovetail mount.
To reinstall it, slide the cube back into the dovetail and secure the retaining screw.
When using the microscope for brightfield, make sure the fluorescence filter cubes are moved out of the optical path. Otherwise, you’ll be viewing the brightfield image through the fluorescence filter.
Activating Fluorescence
To use fluorescence, the appropriate filter cube must be positioned in the light path and the fluorescence shutter must be open.
The shutter control allows you to quickly open or block the fluorescence illumination.
If you’re going to step away from the microscope while leaving the fluorescence system powered on, you can close the shutter to block the illumination until you’re ready to continue working.
LED Fluorescence Illumination
This system is also equipped with a single-channel LED fluorescence illuminator.
With the LED system, you can turn the fluorescence excitation illumination on and off directly with the illuminator control.
Turning the LED off effectively serves the same purpose as closing the fluorescence shutter when you don’t need excitation light reaching the specimen.
Understanding the DIC System
This microscope is also configured for Differential Interference Contrast (DIC).
For DIC to operate correctly, the appropriate optical components must be aligned in the light path.
The system uses an analyzer along with the corresponding DIC prism. The DIC adjustment can then be rotated to change the contrast of the image.
Objective Configuration
This BX51 is equipped with the following objectives:
- 10x
- 20x
- 40x
- 60x
- 100x
The nosepiece can be removed using the same 3 mm Allen wrench.
Locate the retaining screw beside the nosepiece and loosen it approximately a quarter turn. Once loosened, the nosepiece can slide out of the microscope.
Matching the Objective and DIC Prism
Each DIC objective must correspond with the appropriate DIC prism in the condenser.
For example, when using the 10x objective, the system needs to have:
- The 10x objective positioned in the optical path.
- The DIC analyzer inserted.
- The corresponding 10x DIC prism positioned in the condenser.
All three components must be properly aligned for the DIC system to work as intended.
The same principle applies when using the 20x, 40x, and 100x DIC objectives.
Accessing the DIC Prisms
This microscope has a right-handed mechanical stage.
The stage can be removed by loosening its thumbscrew, although we’re going to leave it installed for this demonstration.
To access the condenser, lower it using the substage adjustment. Depending on the position of the stage, you may need to raise the stage slightly to provide enough clearance to remove the condenser.
Loosen the condenser retaining thumbscrew, then use the 3 mm Allen wrench as needed to access the prism assembly.
Inside, you’ll see the individual DIC prisms corresponding to the microscope’s objectives.
For example:
- 10x objective → 10x DIC prism
- 20x objective → 20x DIC prism
- 40x objective → 40x DIC prism
- 100x objective → 100x DIC prism
Using the 60x Objective With This Configuration
This particular customer requested a 60x objective, but did not request a dedicated 60x DIC prism.
However, we found that the 60x objective produces a good image when used with the 100x DIC prism in this particular setup.
This gives the customer an additional option if they want to obtain a DIC-style image while using the 60x objective.
Brightfield Illumination Controls
The Olympus BX51 also provides several controls for conventional brightfield microscopy.
The light intensity knob controls the brightness of the transmitted illumination.
The microscope is also equipped with neutral density and light-balancing filters that can be moved in and out of the light path as needed.
LBD Daylight Blue Filter
One of the most commonly used filters is the LBD daylight blue filter.
With halogen illumination, the light naturally has a warmer color temperature. The LBD filter helps compensate for this and provides a cooler, more neutral-looking illumination through the microscope.
If the brightfield image suddenly looks unusually warm or yellowish, check the LBD filter. It may be missing or simply not pushed into the optical path.
On the BX51, these filters can be easily clicked in and out as needed.
Final Thoughts
That’s the basic overview of this Olympus BX51 fluorescence and DIC microscope.
This configuration combines several imaging capabilities in a single microscope, including:
- Brightfield microscopy
- Fluorescence microscopy
- Differential Interference Contrast (DIC)
- Trinocular imaging for camera use
- Multiple objective magnifications from 10x through 100x
The key with DIC is making sure the objective, analyzer, and corresponding DIC prism are properly aligned. For fluorescence, make sure the appropriate filter cube is in the light path and the fluorescence illumination is activated.
Contact Information
If you have any questions about an Olympus BX51, fluorescence microscopy, DIC configurations, or other microscope equipment, feel free to contact Munday Scientific.
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