Plastic Products

Compact Disc

2006-12-17T22:02:00.000+08:00

Compact Discs are made from a 1.2 mm thick disc of very pure polycarbonate plastic. A thin layer of Super Purity Aluminium (or rarely gold, used for its data longevity, such as in some limited-edition audiophile CDs) is applied to the surface to make it reflective, which is protected by a film of lacquer. The lacquer is normally printed directly and not with an adhesive label. Common printing methods for compact discs are screen-printing and offset printing. CD data is stored as a series of tiny indentations (pits), encoded in a tightly packed spiral track of pits moulded into the top of the polycarbonate layer. The areas between pits are known as 'lands'.

Each pit is approximately 100 nm deep by 500 nm wide, and varies from 850 nm to 3.5 μm of length. The spacing between the tracks, the pitch, is 1.6 μm. A CD is read by focusing a 780 nm wavelength semiconductor laser through the bottom of the polycarbonate layer. The difference in height between pits and lands leads to a phase difference between the light reflected from a pit and from its surrounding land. By measuring the intensity with a photodiode, one is able to read the data from the disc. The pits and lands themselves do not directly represent the zeros and ones of binary data. Instead, Non-return-to-zero, inverted encoding is used: a change from pit to land or land to pit indicates a one, while no change indicates a zero. This in turn is decoded by reversing the Eight-to-Fourteen Modulation used in mastering the disc, and then reversing the Cross-Interleaved Reed-Solomon Coding, finally revealing the raw audio data stored on the disc.

Plastic uses

2006-12-01T10:34:00.000+08:00

Whether you are aware of it or not, plastics play an important part in your life. Plastics' versatility allow it to be used in everything from car parts to doll parts, from soft drink bottles to the refrigerators they get stored in. From the car you drive to work in to the television you watch when you get home, plastics help make your life easier and better. So how is it that plastics have become so widely used? How did plastics become the material of choice for so many varied applications?

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The simple answer is that plastics can provide the things consumers want and need. Plastics have the unique capability to be manufactured to meet very specific functional needs for consumers. So maybe there's another question that's relevant: What do I want? Regardless of how you answer this question, plastics can probably satisfy your needs.

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If a product is made of plastic, there's a reason. And chances are the reason has everything to do with helping you, the consumer, get what you want: Health. Safety. Performance. Value. Plastics help make these things possible.

What Is Plastic?

2006-12-01T10:24:00.000+08:00

A plastic is a type of synthetic or man-made polymer; similar in many ways to natural resins found in trees and other plants. Webster's Dictionary defines polymers as: any of various complex organic compounds produced by polymerization, capable of being molded, extruded, cast into various shapes and films, or drawn into filaments and then used as textile fibers.