How is blue laser better than the red laser?

[Lord Loh.]

I read that the recent development of the blue ray disks that can hold more data than the DVD uses a blue coloured laser that is generated from Galium Nitride.

I was just wondering whether the disperssion of blue laser makes it imprecise???

Doesn't storing more information on less surface require a higher degree of accuracy?

So how is blue laser better than the red laser?

 

[manaman]

Blue Ray disk...

wave length of blue laser is less than that of red this mean more finite structure it can etch ,there by improving the storage capacity , Today thosiba come up with 42GB HD DVD

 

[Lord Loh.]

Blue Ray disk...

So this leads to a question.... Does disperssion come anywhere into picture while focusing ? or is it onlu for parallel beams ?