Here's an interesting bit of news. According to the Japanese newspaper, Nihon Keizai Shimbun, Ricoh has developed a device that can read both Blu-ray and HD DVD discs.
Ricoh Co has developed a device that can read both the Blu-ray and HD DVD next-generation DVD formats, the Nihon Keizai Shimbun reported.

The newspaper, without identifying any sources, said Ricoh was aiming to commercialize this technology as soon as the end of next year.

Blu-ray uses a wider blue laser beam than HD DVD and records data at a distance of 0.1 mm from the surface, while HD DVD records at a distance of 0.6 mm.
If you'd like to read more, the entire article can be found here.