In the development of CD-Rs, one of the most difficult challenges was to create a CD-R that could be accessed by all levels of CD-ROM drives. TDK played a significant role in overcoming this major hurdle.
We created a recording layer with sufficient sensitivity to enable the writing of "pits" with a laser -- while maintaining sufficient reflectivity to enable lower-powered CD players to read those same pits.
The result is that all TDK Recordable Compact Discs can be read by all levels of CD-ROM drives, as well as audio CD players.
TDK Recordable Compact Discs are the first line of blank CD-R media compatible with all types of writing systems, including the latest designs.
With high-speed CD-R writers, the increased rotational velocity results in shortened laser radiation times, causing the recording energy per unit time to be reduced. Under these conditions, serious writing errors will occur if a CD-R does not possess sufficient recording sensitivity. To ensure the lowest possible error rate over the widest range of conditions, TDK has developed a new high-performance recording layer. Made possible by a breakthrough in cyanine dye chemistry, this new material delivers maximum sensitivity and enhanced responsiveness to the modulations of the laser beam.
In addition, TDK CD-R media incorporate proprietary measures to reduce waveform asymmetry -- a major factor in the generation of writing errors at higher speeds.
TDK Recordable Compact Discs feature a protective layer to safeguard from environmental extremes, such as moisture and heat. We developed a highly-effective UV-set resin coating that allow TDK CD-R media to offer unsurpassed durability and outstanding stability under a variety of environment and operating conditions.
The TDK Recordable Compact Disc features a multi-layer structure based on a plastic substrate. The substrate is etched (formatted) with a pregroove which provides timing control and serves as a tracking guide for the laser beam during recording. The substrate is spin-coated with a special organic dye solution, which forms the recording layer. A thin gold layer is vacuum-deposited to provide the reflective characteristics required for playback on conventional CD/CD-ROM equipment. The final coatings are the protective layer and the label film.
During recording, a strong laser beam, modulated by the input signal, is focused through the substrate onto the recording layer. The energy from the laser dissolves the dyes of the recording layer, causing "pits" to form. These pits are areas with an altered refractive index, resulting in the changes of reflectance that can be read by the lower-powered laser pickups in conventional CD-ROM drives and audio CD players.