Light leakage in miniscope body

[thkim3]

Hi everyone,
I have recently assembled  miniscopes and had light leakage problem, which was not detected in the miniscopes I assembled last year.
Applying black enamel paint on the filter edges helped a little but I can still see some light coming in to the CMOS sensor when I put the scope on black surface.
I confirmed that the CMOS sensor and LED parts have nothing to do with the light leakage by swapping the parts with my older miniscopes... It seems that the problem is solely coming from the body(where achromatic lens and filters go in).
The biggest difference between my older miniscopes and new miniscopes is that the inner diameter of the hole where the acromatic lens sits on. The new scopes have much bigger inner diameter than the previous ones. Could it be causing the problem?
Attaching pictures would helped but I couldn't figure out how to upload image files so I tried my best to describe the situation by word...

Thank you.
TaeHyun

[Daniel Aharoni]

Hi thkim3,
If the filter set isn't scratch and placed into the Miniscope correctly, you shouldn't have any light leakage. In an older design, using black enamel paint along the edges of the optical elements could solve light leakage but it shouldn't be necessary any more. Can you upload some pictures of your setup on imgur.com and link them here so I can have a better idea of what your setup looks like. Thanks

[thkim3]

Hi Daniel,
I found that there was a very small scratch I haven't noticed on the excitation filter. Replacing it with a new one solved the problem.
Thanks for advice!