What about a disk that looks like an "E"?
Or since "optical" is in the name, what about making the disk hole an eye?

hhp

I think the lower two signs are not bad, although they could maybe be a little more abstract if you ask me. Although I like the font you've choosen, I don't think it really fits to the sign.
Try to fiddle a bit with the sign. Use, like hhp also said, the 'optical' angle. Have a look here for what they've done with their logo:
http://www.nob.nl/

Try some more. You're on the right track.

Yes, probably Ren

I actually think the squarish font is a nice fit.
What if you make the "O" in "OPTICAL" a disk a leave it at that?

(And "Hrant" is fine.)

hhp

(And "Hrant" is fine.)

Big Papa is better.

That makes me sound like an African warlord. Cool.

hhp

just a tidbit: the fifth - (bottom right corner) is almost excatly the same as a curling association logo (forget the name sorry) but they have the circles coloured 1 red and 1 blue - otherwise same shape and detail

Thank you all, guys, for you rpositive responce. I gave the 4 finalists to the client, so now I'm waiting for him to decide. And meanwhile let me show you something I think the client would probably approve (sadly, but true)

The ED treatment reminds me of the IMSFA ED logo posted by Cristian G in Feb.

Andrew

Could you be more specific, I would like an URL...and honestly, I haven't seen IMSFA ED logo. But I'm sure that this certain combination of E & D is a bit overused, maybe because it is too obvious

Sorry. Here it is.

http://www.typophile.com/forums/messages/29/26754.html?1077302617

My first reaction: "Hmmm. I like the top version."

My second reaction: "What if the line which indicated the center piece of the cds (in the bottom right version) was the same weight as that pseudo-connecting line?"

I prefer the squat-square typeface too.