Unformatted text preview: ns between the electronic devices speciﬁc properties to achieve an optimum design.
Let us examine the major components of a camcorder. The has a signiﬁcant inﬂuence on the reliability of the circuits and lenses must transmit light without optical aberrations to achieve therefore the performance of the camcorder. This quality can be a high-quality picture. Lenses are made from glasses, which owe assured only if sufﬁcient diffusion (atomic scale mixing) occurs their transparency to their noncrystalline structure. The hardness between the materials being bonded together. As discussed in of glass, which makes it suitable for precision grinding to achieve Chapter 4, the diffusion required to produce a strong bond be- the proper lens shape, is a consequence of its three-dimensional tween materials would not be practical without the presence of bond network, as discussed in Chapters 2 and 6. point defects in crystals. Camcorders also contain small, intri- The camcorder housing parts must be light and easily formed cately machined metal parts such as gear and sprocket assemblies into intricate shapes. These components are made from polymers that could not have been produced economically without the composed of molecular chains of light elements that are loosely presence of line defects known as dislocations. As described in packed together resulting in a low-density material. Since the Chapter 5, dislocations make metals easy to form and machine molecular chains are attached to each other by weak secondary into complicated shapes. bonds, which disintegrate easily upon heating, these materials In sum, a camcorder, or any other complex commercial product, have low softening points, which permit them to be shaped inex- is composed of many components, each requiring a different pensively. The structure of polymers will be discussed in Chap- combination of properties such as strength, formability, and re- ters 2 and 6. sponse to electric ﬁelds. The job of the materials engineer, or any
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