Blurry images with 100x

Hello all,

Thank you for the great project! I’ve build OFM to make pictures of ICs (Integrated Circuits).
I was able to make pictures of old one from 80’s but when I try to make pictures of newer ones 00’s processors I see that pictures are blurry.

I wonder if it possible to make it less blurry or I am reaching some kind of limit?

Thanks in advance

Which version of the Openflexure microscope are you using, including which optics version and camera?

There is a strong colour cast on those images, have you run the camera calibration routine in the software? It looks as though the object is slightly tilted - it is more in focus at the top left than the bottom right.

A photograph of your build may also help to see what is happening.

Hello WilliamW thank you for swift reply!

I am using OpenFluxture Connect 4.0.1
Raspberry pie camera module 2.
The optic is AmScope Plan 100/1.25 160/0.17
I’ve followed all the steps of standard build

After full calibration it helped with color space but still it looks blurry.

You are using the reflection optics, which I should have thought about as chips are not transparent. I have not got any direct experience of that, but I think the alignment of the illumination is tricky. You do appear to have very weak illumination at the bottom right, which in itself is not a problem, but means that you are not focusing at the centre of the image, but in the brighter part of the top left. With a 100x 100/1.25 160/0.17 objective a lot of things are important to get a good image. The depth of field is very small (about 1µm or less), so the sample does need to be very level for it to be all in focus. The objective is designed for oil immersion between the sample and the lens, with a cover glass thickness of 0.17mm. If you are not using immersion oil, or your sample does not have a cover glass then the lens is not operating according to the design and will not focus as well. The focus will always be worse at the edges, and will be even worse if teh lens is used away from the design parameters. Finally the illumination needs to be good, in that you need to be illuminating at all angles, including high angles, in order to get high resolution. That is slightly easier in reflection mode as the same high NA lens is used for illumination as for the imaging, but it still takes care.
So I would suggest first trying to get the illumination better centred, and use immersion oil if you are not already doing so.

The 100/1.25 160/0.17 type lens is often described as a biological microscope lens, the sample is in water, covered by a coverslip, and then use oil immersion to get very high NA and high resolution. For dry surface samples, like a bare chip or a mineral sample, it would be a ‘metallurgical’ microscope lens. These are designed for a bare sample in air. However they tend to be much more expensive, and there is a fundamental limit to the resolution as the NA possible in air is lower than in oil. Usually 0.55NA would be used, which still gives high resolution, although not sub-micron.