Ricoh has reportedly invented a technology, which allows a single laser to read and write all currently available types of optical discs, e.g., Blu-ray discs, CDs, DVDs and HD DVDs. Potentially, this may end the format war in the consumer electronics space, as all manufacturers will be able to support both competing standards – Blu-ray and HD DVD – without much additional spending.
The data layer of the Blu-ray discs is located 0.1mm from the disk’s surface, whereas the HD-DVD data layer has data layer depth of 0.6mm from the disk’s surface, the same as DVD disks, meanwhile CD’s data layer resides 1.1mm deep from the disk surface. In order to read or record the data, laser beam needs to be adjusted appropriately. According to EETimes web-site, Ricoh has invented a special component, which – a diffraction plate – which can “target” the laser beam at an appropriate data layer.
The 3.5mm diameter, 1mm thick round diffraction plate with minute concentric groves on both sides which function as a diffraction grating 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.
Multi-format optical disc readers and recorders can recognize which format media is loaded. When the format is clear, Ricoh’s optical diffraction element 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, the web-site cites the company as saying.
“This diffraction device is the first one that is ready for four formats, including BD and HD-DVD. It will make it possible to build players and recorders ready for all formats, which will benefit consumers,” a Ricoh spokesman is reported to have said.
Ricoh will demonstrate the device at International Optoelectronics Exhibition ‘06 outside