DVD Technology—A Synopsis

April 16, 2001
Do you want to put your DVDs in your refrigerator or your hot water heater? Although it sounds silly, you could do so without damaging the disks. DVDs have an unusually wide operating temperature range (­25°C to 70°C). They are made...

Do you want to put your DVDs in your refrigerator or your hot water heater? Although it sounds silly, you could do so without damaging the disks. DVDs have an unusually wide operating temperature range (­25°C to 70°C). They are made from transparent materials, such as acrylics, polyolefins, and polycarbonates. The 1.2-mm thick disk comprises two substrates bonded together. Each 0.6-mm substrate can contain one or two layers of data. The layer closest to the side from which it's read is called layer 0 (see the figure). The other layer is called layer 1. These layers are spaced quite closely together (55 µm), which is about 1/20th of the disk's overall thickness.

The optical pickup mounts the laser (or lasers) and associated electronic circuitry. The pickup is mounted on an arm that dynamically positions it under the disk moving in and out laterally, as required, so as to read different tracks. The pickups employ semiconductor red lasers at 635 or 650 nm. Because the data is stored at various depths, techniques have been devised to control the focus depth.

Sponsored Recommendations

Highly Integrated 20A Digital Power Module for High Current Applications

March 20, 2024
Renesas latest power module delivers the highest efficiency (up to 94% peak) and fast time-to-market solution in an extremely small footprint. The RRM12120 is ideal for space...

Empowering Innovation: Your Power Partner for Tomorrow's Challenges

March 20, 2024
Discover how innovation, quality, and reliability are embedded into every aspect of Renesas' power products.

Article: Meeting the challenges of power conversion in e-bikes

March 18, 2024
Managing electrical noise in a compact and lightweight vehicle is a perpetual obstacle

Power modules provide high-efficiency conversion between 400V and 800V systems for electric vehicles

March 18, 2024
Porsche, Hyundai and GMC all are converting 400 – 800V today in very different ways. Learn more about how power modules stack up to these discrete designs.

Comments

To join the conversation, and become an exclusive member of Electronic Design, create an account today!