Recordable compact discs

Figure 9.45 Organic dyes have a variety of useful applications, from the production of colorful fabrics (left) to the production of laser-recordable compact discs (CD-R discs) for computer data storage (right). 

The most successful application of near infrared radiation absorbing phthalocyanine compounds is in material for recordable compact discs (CD-R). According to the international standard specification, recording materials for CD-R must have an absorption maximum around 780 nm, which wavelength permits both recording and read out. The thickness, refractive index, and extinction coefficient of the recording material are all optimized to increase the reflectance of the recording layer. 

Munoz RAA, Matos RC, Angnes L (2001) Amperometric detramination of dipyrone in pharmaceutical formulations with a flow cell containing gold electrodes from recordable compact discs. J Pharm Sci 90 1972-1977... 

For many years vinyl chloride-vinyl acetate copolymers had two main uses, in flooring compositions and for long playing gramophone records. Whereas the former application remains strong, the use in gramophone records has dropped sharply, particularly since the widespread acceptance of polycarbonate-based compact discs. 

Iowa Drug Information Service. A bibliographical database with access to full text, IDIS [98] provides access to the therapeutic and clinical pharmaceutic English language journal literature from 17 countries. FDA Summary Basis of Approval documents are indexed and available in full text. Updated monthly, the database contains over 450,000 records from 1966 forward with bibliographic citation, keyword indexes, and, for over 60% of citations, the author s abstract. IDIS is commercially available in microfiche, compact disc, and web formats and via DataStar, DIALOG. 

Compact discs (CDs), which may be found in over 25 million American homes, not to mention backpacks and automobiles, first entered popular culture in the 1980s. But their history goes back to the 1960s, when an inventor named James Russell decided to create an alterna-(5) five to his scratched and warped phonograph records—a system that could record, store, and replay music without ever wearing out. 

Optical applications storage media, CD, CD-ROM, DVD, SACD (super audio compact disc) lenses for cameras on mobile phones, digital cameras, compact cameras, CD-players, video recorders... 

The storage and retrieval of data by optical means, which involves the interaction of some medium with a compact laser, focused to sub-micron size, is dominated by direct bit storage onto disc media. The various types of storage media, from read only compact discs (CD-ROM) to rewritable digital versatile discs (DVD-RW), and the favoured recording materials are shown in Figure 4.5. ... 

Pick-up lenses for digital versatile disc (DVD) players, recorder and super audio compact disc players,... 

Heat. As mentioned above most molecules lose energy from the excited state as heat. The most efficient molecules for converting electromagnetic radiation into heat are those that absorb in the near-IR region, i.e., infrared absorbers (IRAs). There has been much interest in IRAs because of their use in laser thermal transfer, optical data storage [the older write-once read-many (WORM) and the newer compact disc recordable (CD-R) and digital versatile disc recordable (DVD-R) systems], computer-to-plate printing, and as solar screens for car windscreens and windows. 

The world has seen the rise and demise of record albums, eight-track tapes, and cassette tapes, one has to wonder what will follow compact discs. 

Dithiolene complexes, and more specifically the nickel derivatives, are involved in materials used for optical data storage, such as compact disc or laser disc read-only memory (CD- or LD-ROM), and also in copiers or photography related devices. In the latter case, it is the IR-absorbing property that is exploited. Some of these compounds can be found in reviews by Mueller-Westerhoff et al. (353, 354). Recent patents are given as examples in references (458—481). In the field of optical storage, short reviews were published in 1988 (482) and 1990 (362, 483). Here, the dithiolene complexes act as inhibitors of the laser-induced fading of the colored thin layers of the optical discs. They also act as an antioxidant and increase the photostability of the cyanine dyes that constitute the recording layer. Contrary to what was observed for the two... 

Recordable and rewritable CD devices are becoming popular but strictly speaking, they are not CD-ROMs. Technically, these devices are called rewritable compact discs. 

Nicad batteries are used in a large variety of appliances, including compact disc players, cell phones, pocket recorders, handheld power tools, cordless telephones, laptop computers, camcorders, and scanner radios. A few automobile manufacturers have explored the possibility of using nicad batteries in electric cars. For example, the Mitsubishi Corporation of Japan built and marketed an experimental car called the Libro EV that operated on either traditional lead batteries or on nicad batteries. 

The potential application of this glass is in high-density optical recording (used, for example, in compact disc players). In such devices the information density increases with dccrca.sing sire of the focus spot of the laser. This sire varies inversely quadratically with the wavelength. Since the available diode lasers emit in the near infrared, there is a considerable amount of research going on to obtain a blue-emitting diode laser. There are three possibilities, viz. 

The compact disc (CD) was invented in 1965 by James Russell, who was actually granted 22 different patents for the various parts of the CD playing and recording system. But it was not until the early 1980s, when... 

As an example of an optical recording medium. Figure 1 shows schematically the construction of a Compact Disc (CD). 

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