Researchers at National Taiwan University say that groups developing next-generation DVD players may not have to use blue lasers as expected (US 2004/32822).
The short wavelength of blue lasers means they can focus on smaller data spots – the dots and dashes etched into the disc that encode the content. But blue lasers are hard to make. NTU says the spots on high-density discs can be read with cheaper red lasers, if the disc is coated with a lensing layer.
The lens layer comprises several coatings of zinc oxide. Refraction at these oxide layers focuses the red light, giving the…
