an style="font-family:微软雅黑, sans-serif;font-size:16px">石英晶体俗称水晶an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">成份是an>an style="font-size:16px">SiO2,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">它不但是较好的光学材料an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">而且是重要的压电材料。石英晶振在常压下不同温度时an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">石英晶体的结构是不同的。温度低于an>an style="font-size:16px">573an>an style="font-family:微软雅黑, sans-serif;font-size:16px">℃时an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">是an>an style="font-size:16px">aan>an style="font-family:微软雅黑, sans-serif;font-size:16px">石英晶体an>an style="font-size:16px">;an>an style="font-family:微软雅黑, sans-serif;font-size:16px">温度在an>an style="font-size:16px">573an>an style="font-family:微软雅黑, sans-serif;font-size:16px">℃an>an style="font-size:16px">~870an>an style="font-family:微软雅黑, sans-serif;font-size:16px">℃时an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">是an>an style="font-size:16px">Ban>an style="font-family:微软雅黑, sans-serif;font-size:16px">石英晶体an>an style="font-size:16px">;an>an style="font-family:微软雅黑, sans-serif;font-size:16px">温度在an>an style="font-size:16px">870an>an style="font-family:微软雅黑, sans-serif;font-size:16px">℃an>an style="font-size:16px">~1470an>an style="font-family:微软雅黑, sans-serif;font-size:16px">℃时an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">是磷石英an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">温度达an>an style="font-size:16px">1470an>an style="font-family:微软雅黑, sans-serif;font-size:16px">℃时an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">就转变成方石英an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">它的熔点是an>an style="font-size:16px">1750an>an style="font-family:微软雅黑, sans-serif;font-size:16px">℃。用于制造压电晶体元件的为an>an style="font-size:16px">aan>an style="font-family:微软雅黑, sans-serif;font-size:16px">石英晶体,石英晶振.an>
an style="font-family:微软雅黑, sans-serif;font-size:16px">§an>an style="font-size:16px">1-1an>an style="font-family:微软雅黑, sans-serif;font-size:16px">石英晶体的结晶形态和坐标系an>
an style="font-family:微软雅黑, sans-serif;font-size:16px">固体可以分为结晶体an>an style="font-size:16px">(an>an style="font-family:微软雅黑, sans-serif;font-size:16px">晶体an>an style="font-size:16px">)an>an style="font-family:微软雅黑, sans-serif;font-size:16px">与非结晶体an>an style="font-size:16px">(an>an style="font-family:微软雅黑, sans-serif;font-size:16px">非晶体an>an style="font-size:16px">)an>an style="font-family:微软雅黑, sans-serif;font-size:16px">两大类。晶体中有外形高度对称的单晶体an>an style="font-size:16px">(an>an style="font-family:微软雅黑, sans-serif;font-size:16px">如石英晶体an>an style="font-size:16px">)an>an style="font-family:微软雅黑, sans-serif;font-size:16px">和由许多微细晶体组成的多晶体an>an style="font-size:16px">(an>an style="font-family:微软雅黑, sans-serif;font-size:16px">如各种金属an>an style="font-size:16px">)an>an style="font-family:微软雅黑, sans-serif;font-size:16px">。石英贴片晶振的主要特性是原子和分子的有规则排列an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">这种排列反映在宏观上是外形的对称性an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">而非晶体就不具备这种特性an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">例如石英玻璃an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">它的成份与石英晶体一样是an>an style="font-size:16px">SiO2,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">但不属于晶体。an>
an style="font-family:微软雅黑, sans-serif;font-size:16px">晶体可以是天然的an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">也可以由人工培养。晶态物质在适当条件下an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">能自发地发展成为一个凸多面体形的单晶体。围成这样一个多面体的面称为晶面an>an style="font-size:16px">;an>an style="font-family:微软雅黑, sans-serif;font-size:16px">晶面的交线称为晶棱an>an style="font-size:16px">;an>an style="font-family:微软雅黑, sans-serif;font-size:16px">晶棱的会集点称为顶点。发育良好的单晶体an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">外形上最显著的特征是晶面有规则的配置an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">属于同一品种的石英晶振晶体an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">两个对应晶面an>an style="font-size:16px">(an>an style="font-family:微软雅黑, sans-serif;font-size:16px">或晶棱an>an style="font-size:16px">)an>an style="font-family:微软雅黑, sans-serif;font-size:16px">间的夹角恒定不变。图an>an style="font-size:16px">1.1.1an>an style="font-family:微软雅黑, sans-serif;font-size:16px">给出了理想石英晶体的外形。石英晶体的晶面共an>an style="font-size:16px">30an>an style="font-family:微软雅黑, sans-serif;font-size:16px">个an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">分为五组an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">六个an>an style="font-size:16px">man>an style="font-family:微软雅黑, sans-serif;font-size:16px">面an>an style="font-size:16px">(an>an style="font-family:微软雅黑, sans-serif;font-size:16px">柱面an>an style="font-size:16px">),an>an style="font-family:微软雅黑, sans-serif;font-size:16px">六个an>an style="font-size:16px">Ran>an style="font-family:微软雅黑, sans-serif;font-size:16px">面an>an style="font-size:16px">(an>an style="font-family:微软雅黑, sans-serif;font-size:16px">大棱面an>an style="font-size:16px">),an>an style="font-family:微软雅黑, sans-serif;font-size:16px">六个an>an style="font-size:16px">ran>an style="font-family:微软雅黑, sans-serif;font-size:16px">面an>an style="font-size:16px">(an>an style="font-family:微软雅黑, sans-serif;font-size:16px">小棱面an>an style="font-size:16px">)an>an style="font-family:微软雅黑, sans-serif;font-size:16px">六个an>an style="font-size:16px">san>an style="font-family:微软雅黑, sans-serif;font-size:16px">面an>an style="font-size:16px">(an>an style="font-family:微软雅黑, sans-serif;font-size:16px">三方双锥面an>an style="font-size:16px">),an>an style="font-family:微软雅黑, sans-serif;font-size:16px">六个an>an style="font-size:16px">xan>an style="font-family:微软雅黑, sans-serif;font-size:16px">面an>an style="font-size:16px">(an>an style="font-family:微软雅黑, sans-serif;font-size:16px">三方偏方面an>an style="font-size:16px">),an>an style="font-family:微软雅黑, sans-serif;font-size:16px">相邻an>an style="font-size:16px">man>an style="font-family:微软雅黑, sans-serif;font-size:16px">面的夹角为an>an style="font-size:16px">60an>an style="font-family:微软雅黑, sans-serif;font-size:16px">°相邻an>an style="font-size:16px">man>an style="font-family:微软雅黑, sans-serif;font-size:16px">面和an>an style="font-size:16px">Ran>an style="font-family:微软雅黑, sans-serif;font-size:16px">面的夹角与相邻an>an style="font-size:16px">man>an style="font-family:微软雅黑, sans-serif;font-size:16px">面和an>an style="font-size:16px">ran>an style="font-family:微软雅黑, sans-serif;font-size:16px">面的夹角都等于an>an style="font-size:16px">38an>an style="font-family:微软雅黑, sans-serif;font-size:16px">°an>an style="font-size:16px">13,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">相邻an>an style="font-size:16px">san>an style="font-family:微软雅黑, sans-serif;font-size:16px">面与an>an style="font-size:16px">xan>an style="font-family:微软雅黑, sans-serif;font-size:16px">面的夹角等于an>an style="font-size:16px">25an>an style="font-family:微软雅黑, sans-serif;font-size:16px">°an>an style="font-size:16px">57an>an style="font-family:微软雅黑, sans-serif;font-size:16px">。由于外界条件能使某一个或某一组晶面相对地变小或完全隐没an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">所以实际见到的石英晶体很少如图an>an style="font-size:16px">1.1.1an>an style="font-family:微软雅黑, sans-serif;font-size:16px">所示an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">就是人造石英晶振,石英晶体振荡器,石英晶体的外形也只是接近理想情况。an>
an style="font-size:16px">(a)an>an style="font-family:微软雅黑, sans-serif;font-size:16px">右旋石英晶体an>an style="font-size:16px"> (b)an>an style="font-family:微软雅黑, sans-serif;font-size:16px">左旋石英晶体an>
an style="font-family:微软雅黑, sans-serif;font-size:16px">图an>an style="font-size:16px">1.1.1an>an style="font-family:微软雅黑, sans-serif;font-size:16px">石英晶体的理想外形an>
an style="font-family:微软雅黑, sans-serif;font-size:16px">晶体内部结构的规律性an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">造成了它在外形上的对称性。例如an>an style="font-size:16px">:an>an style="font-family:微软雅黑, sans-serif;font-size:16px">晶体可以有对称轴、对称中心、对称面等对称元素。石英晶振晶体存在一个三次对称轴an>an style="font-size:16px">(an>an style="font-family:微软雅黑, sans-serif;font-size:16px">或三次轴即晶体绕该轴旋an>an style="font-size:16px">360an>an style="font-family:微软雅黑, sans-serif;font-size:16px">°an>an style="font-size:16px">3an>an style="font-family:微软雅黑, sans-serif;font-size:16px">后能够复原an>an style="font-size:16px">)an>an style="font-family:微软雅黑, sans-serif;font-size:16px">和三个互成an>an style="font-size:16px">120an>an style="font-family:微软雅黑, sans-serif;font-size:16px">°的二次轴an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">如图an>an style="font-size:16px">1.1.2an>an style="font-family:微软雅黑, sans-serif;font-size:16px">中的an>an style="font-size:16px">aan>an style="font-family:微软雅黑, sans-serif;font-size:16px">、an>an style="font-size:16px">ban>an style="font-family:微软雅黑, sans-serif;font-size:16px">、an>an style="font-size:16px">dan>an style="font-family:微软雅黑, sans-serif;font-size:16px">轴an>
an style="font-family:微软雅黑, sans-serif;font-size:16px">图an>an style="font-size:16px">1.1.2an>an style="font-family:微软雅黑, sans-serif;font-size:16px">石英晶体的对称轴和直角坐标系an>
an style="font-family:微软雅黑, sans-serif;font-size:16px">在结晶学中an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">晶体的内部结构可以概括为是由一些“点子”在空间有规则地作周期的无限分布an>an style="font-size:16px">:an>an style="font-family:微软雅黑, sans-serif;font-size:16px">“点子”代表原子、离子、分子或其集团的重心。这些“点子”的总体称为点阵an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">构成石英晶振,有源晶振,石英晶体的是二氧化硅分子an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">而二氧化硅分子的重心又正好与硅离子重合an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">因此硅离子的点阵就可以反映出石英晶体的内部结构。石英晶体的各层硅离子若按右手螺旋规则分布an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">则称为右旋石英晶体an>an style="font-size:16px">;an>an style="font-family:微软雅黑, sans-serif;font-size:16px">若按左手螺旋规则分布an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">称为左旋石英晶体。从外形上看an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">右旋石英晶体的an>an style="font-size:16px">san>an style="font-family:微软雅黑, sans-serif;font-size:16px">面在an>an style="font-size:16px">Ran>an style="font-family:微软雅黑, sans-serif;font-size:16px">面的右下方或an>an style="font-size:16px">man>an style="font-family:微软雅黑, sans-serif;font-size:16px">面的左上方an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">左旋石英晶体的an>an style="font-size:16px">san>an style="font-family:微软雅黑, sans-serif;font-size:16px">面在an>an style="font-size:16px">Ran>an style="font-family:微软雅黑, sans-serif;font-size:16px">面的左下方或an>an style="font-size:16px">man>an style="font-family:微软雅黑, sans-serif;font-size:16px">面的右上方an>an style="font-size:16px">(an>an style="font-family:微软雅黑, sans-serif;font-size:16px">见图an>an style="font-size:16px">1.1.1),an>an style="font-family:微软雅黑, sans-serif;font-size:16px">它们互为镜象对称。an>
an style="font-family:微软雅黑, sans-serif;font-size:16px">石英晶振晶体物理性质的各向异性和晶体外形的对称性有关an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">因此讨论石英晶体的物理性质时an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">采用为图an>an style="font-size:16px">1.1.2an>an style="font-family:微软雅黑, sans-serif;font-size:16px">所示的直角坐标系较为方便。选an>an style="font-size:16px">can>an style="font-family:微软雅黑, sans-serif;font-size:16px">轴为an>an style="font-size:16px">zan>an style="font-family:微软雅黑, sans-serif;font-size:16px">轴an>an style="font-size:16px">,a(an>an style="font-family:微软雅黑, sans-serif;font-size:16px">或an>an style="font-size:16px">ban>an style="font-family:微软雅黑, sans-serif;font-size:16px">、an>an style="font-size:16px">d)an>an style="font-family:微软雅黑, sans-serif;font-size:16px">轴为an>an style="font-size:16px">xan>an style="font-family:微软雅黑, sans-serif;font-size:16px">轴an>an style="font-size:16px">,an>an style="font-family:微软雅黑, sans-serif;font-size:16px">与an>an style="font-size:16px">xan>an style="font-family:微软雅黑, sans-serif;font-size:16px">轴、an>an style="font-size:16px">zan>an style="font-family:微软雅黑, sans-serif;font-size:16px">轴垂直的轴为an>an style="font-size:16px">yan>an style="font-family:微软雅黑, sans-serif;font-size:16px">轴。其指向按an>an style="font-size:16px">1949an>an style="font-family:微软雅黑, sans-serif;font-size:16px">年an>an style="font-size:16px">IREan>an style="font-family:微软雅黑, sans-serif;font-size:16px">标准规定对左、右旋石英晶体均采用右手直角坐标系。an>