U-RLA Vertical Illuminator Purple Glare

houstontx · Post by **houstontx** » Sat Mar 25, 2017 10:20 pm

Hi All,

I am seeing a purple spot or glare over the image using the BX U-RLA Vertical Illuminator on a BX40. I am attaching a picture of the issue. This was taken through the eyepiece with the aperture iris wide open, field iris closed down all the way and then purposefully moved off center to better see the purple spot.

With a rotateable polarizer inserted it helps a little on cutting down the glare spot. But even with the iris open and image centered there is always a faint tinge of purple.

I am using zeiss CP-Achromat 5x and 10x from an axiostar unit. The images look very good but just have the purple coloring. Could the issue be because I am not using olympus objectives?

Thanks,

Pau · Post by **Pau** » Sun Mar 26, 2017 1:51 am

Do you have filters installed over the half mirror of the vertical illuminator?
I have experienced this issue after putting two filters at that position in my fluorescence epi illuminator.
Some systems put that filter (the analyzer I suppose in your case) a bit angled, about 5º, to avoid reflections.
I don't think that the culprit will be the objective, but I don't really know.

houstontx · Post by **houstontx** » Mon Mar 27, 2017 10:49 am

Pau,

There are no filters inserted (ND type or others) and no sliders (pol type) when the issue occurs. The only way to cut down the glare spot is to insert a rotatable polarizer in the horizontal slot directly above the nosepiece.

The only issue I am thinking now is the light source. I am using a stryker x6000 illuminator connected to a schott fiber optic cord and U-ADR adapter connected directly to the U-RLA. It provides pretty uniform illumination but its not the typical OEM setup.

Pau · Post by **Pau** » Mon Mar 27, 2017 11:06 am

If the microscope is bundled with a substage condenser and you put the sample on a glass slide try masking it with a black material, removing it or even playing with its height while observing the spot.
If crossed polarizers suppress it, it sounds to me that the culprit could be at the subject position (reflection on glass slide surface) or under it (substage condenser) ...just possibilities

houstontx · Post by **houstontx** » Wed Mar 29, 2017 9:25 pm

Sorry to drag this up. It looks like the issue is definitely worse with the 5x objective. I think the culprit may be the pull tab with the small dot. Not sure what this is, some kind of pinhole slider? I cant find a manual for the U-RLA online. Here is a picture of a butterfly wing thru 5x and 10x objective, as well as the slider knob. I think this glass might be loose and causing the reflection glare...Not sure if I can remove it?

harisA · Post by **harisA** » Thu Mar 30, 2017 12:24 am

Have faced similar problems with epi illumination.They always appeared when using objectives from biological microscopes with epi.Try to use a metallurgical objective.