CD and DVD area

[Jean-marc]

Hello,

After the very good subject of C.Krebs and Gerd, I tried to see the pits and lands. I tried with my own written CD and DVD, but the images were not good at all, I . So I tried with old already printed CD and DVD.
It was easier and you know what you are looking at.

The first shot is CDR (bottom) and DVDR (top) I wrote myself

You can see the grooves lands and I think the "pré-pits"
Those images are not really good, I am not satisfied

épi brightfield splanapo 100/1,40 for the two parts. The objective is not well corrected for reflected light. The scale is 10µm



This image is a CD printed. The two parts are made with splanapo 40/0,95 with reflected light and DIC
The field is 200µm x 140µm



This image is a DVD printed. The top is épi brightfield, and the bottom is reflected light with DI. The two are with splanapo 40/0,95
The field is 200µm x 140µm



Those two last images show what I suppose the pits, the DIC help very well to see the them.

I benefit this subject to wish at all the forum an happy new year

Jean-Marc

[rjlittlefield]

Nice images!

I'm curious how these are prepared. In a DVD the reflecting layer is buried about 0.6 mm inside the polycarbonate, so I'm thinking that a dry high-NA objective designed for either no cover glass or standard cover glass would have huge spherical aberration looking through the extra plastic. Did you shoot these with oil immersion, or shatter the disk to delaminate it, or is the problem not as bad as I think?

--Rik

[Jean-marc]

Hi Rik, thank you,

You are right, I separated the 2 layers to be able to see them. My 40x Splanapo have a too short working distance to see through the plastic. To avoid any aberration, I put a 0,17mm slide (without medium) on the layer, them I adjust the sharpness with the corrector ring of the objective.

Thank you

Regards

JM

[curt0909]

Great results. I tried this with a metallurgical microscope without removing the plastic cover and couldn't visualize any pits. Nice job.