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随着电子设备的微小型化、集成化、印制电路也愈来愈复杂,正向着高精度、高密度和高可靠性方向发展。印制电路板已从单面发展到双面、多层和挠性印制电路。印制电路在整个电子产品中所占的比例也正在逐渐增加。美国从1945年开始应用印制电路,至今年产值已达30亿美元,每年递增22％。计算机工业是它的最大用户。日本从1955年开始生产印制线路板,有二百多家工厂,其中90％以上是中小企业,在最近五、六年内,年增长率超过10％。1977年总产值为1176亿日元,约为5亿美元。技术水平的标志,典型产品和典型工艺印制电路的技术水平是以2.54毫米的标准座标格上,两个焊盘间能通过几根导线来标志的。两个焊盘直径各为1.5毫米,能通
With the miniaturization and integration of electronic devices, the printed circuit is also becoming more and more complex, and is moving toward high precision, high density and high reliability. Printed circuit boards have evolved from single-sided to double-sided, multilayer and flexible printed circuits. Printed circuit in the proportion of the entire electronic product is also gradually increasing. Since 1945, the United States began to apply printed circuits, reaching an annual output value of 3 billion U.S. dollars, an increase of 22% annually. Computer industry is its largest user. Japan began producing printed circuit boards in 1955 with more than 200 factories, of which over 90% are small and medium-sized (SMEs), with an annual growth rate of over 10% in the last five or six years. In 1977 the total output value of 117.6 billion yen, about 500 million US dollars. Technical level of the logo, typical products and typical technology printed circuit technology standard is 2.54 mm standard cell, the two pads can be marked by a few wires. Two pads each 1.5 mm in diameter, can pass