Ricoh develops component that reads Blu-ray & HD-DVD discs

The component is a 3.5-mm diameter, 1-mm thick round diffraction plate with minute concentric groves on both sides which function as a diffraction grating.

The diffraction plate is placed between lasers and an objective lens. The diffraction grating is designed to adjust a light beam to an optimum incident ray relative to the objective lens so that light focuses on the proper position for each disk format.

The data layer of the Blu-ray Disc resides 0.1 mm from the disk’s surface, while the HD-DVD data layer is 0.6-mm deep from the disk’s surface, the same as DVD disks. Cd’s have a data layer depth of 1.1 mm from the disk surface.

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>Multiformat players and recorders can identify which format disk is loaded. Based on the disc information, Ricoh’s optical diffraction component adjusts the laser beam with its diffraction grating for each format and passes it to the objective lens. The lens then forms a beam spot at the appropriate depth for each disk format.

“This diffraction device is the first one that is ready for four formats, including BD and HD-DVD,” claimed a Ricoh spokesman. “It will make it possible to build players and recorders ready for all formats, which will benefit consumers,” he added.