up to relatively recently blue LEDs were very expensive to manufacture. however they managed to find a way which is another reason for the flat screened TVs have suddenly burst onto the market.because a tv piccy is made up of red ,green and blue.up until say 3 years a red led would cost 2p an equivalent blue was about �5.
these days the red is still 2p and the blue 20p.so I suppose the more demand will bring the manufacturing price down.It is all to do with the wavelength of blue!!!