Video compact disks

The CD-I (compact disk-interactive) is a low cost alternative to the CD-ROM for the entertainment industry. CD-I is a subset of the CD-ROM standard data format. It allows the digital storage of data, audio, and video information in a form that permits rapid interaction with a computer. CD-I is compatible to CD-ROM and to CD-AD 0 = 120 mm. The definition of the CD-I format is put down in the Green Book (Philips/Sony). 

CD-V (compact disk-video) is premolded for both video and digital music 0 = 305 mm oi0 = 203 mm. There is also a videocHp version (0 = 120 mm) for 22 min CD audio and 5 min of video information. CD-VEP (video extended play) 0 = 200 mm, is recorded on both sides, whereas for CD-VLP (video long play) 0 = 200 mm, one- or two-sided recording can be selected max. 60 min video/side. 

A total of 15,000—17,000 t of resin is used aimuaHy. Polycarbonate also has many technical uses in instmment panels and devices, especiaHy for membrane switches and insulators. Optical quaHty polycarbonate is the only suitable material for the compact disk market. Since their introduction in 1983, compact disks have shown explosive growth in the consumption of polycarbonate, with utiHty for audio, video, and computer appHcations. Consumption of optical quaHty resin more than doubled between 1988 and 1992, and as of 1995 accounted for about 20,000 t of annual production. 

Storage on modern systems, if drives for removable disks, writable CDs (compact disks), CD-ROMs (compact disk, read-only memory), DVDs (digital video disk), and magnetic tapes are allowed or there are network connections to servers with large-capacity storage devices where data can be stored, is virtually infinite. 

One of the most popular systems is a laser disk for audio known as a compact disk (CD), in which PCM signals are recorded on the rear side of a plastic transparent disk and laser light reads them as shown in Fig. 20. A digital video... 

There is a wide variety of sources of information available which can be classified by the medium used. The main ones are paper-based materials such as books and periodicals computer-based materials such as on-line databases and CD-ROM (Compact Disk - Read Only Memory) and other media including videos, film and microfiche. 

The optical disk market is a major PC consumer and, according to Bayer Material Science, it accounts for 800,000 tonnes out of a global market of around 2.4 million tonnes. In the UK, compact disks (CD) and digital video disks (DVD) are frequently given away with newspapers and there is a vast market for DVD versions of popular films with the film, Shrek 2 generating worldwide sales of approximately 40 million optical disks. 

Laser diodes are used in a variety of applications. Most bar-code scanners are now based on laser diodes (previously, they used He-Ne lasers). Optical media, such as compact disks (CDs), digital video disks (DVDs), and Blu-ray disks, use laser diodes given the proliferation of personal media devices in many societies, it is understandable that laser diodes are the most common form of laser. Laser diodes are also used in fiber-optic communications. Because they can be made very small (Figure 15.38), laser diodes can be used in applications where other types of lasers are precluded because of space, size, or power limitations. 

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