I found this link in avsforums and think it`s interesting, the thing is quite a complex construction
http://www.fineartradiography.com/hobbies/lasers/blu-ray/optics.html
The optical assembly contains some very strange and novel optics, unlike anything ever seen in an optical pickup before
http://www.fineartradiography.com/hobbies/lasers/blu-ray/optics.html