1.前言最近要求机床大型化、高精度化和高效率而装上数字控制装置或数字式位置指示装置。此时,位置检测器是不可缺少的,它必须具备下列条件: (1)精度高,无累积误差; (2)性能随着时间的变化少,稳定,可靠性高; (3)温度、湿度的影响少; 1. Introduction Recently, large-scale machine tools have been demanded, and high-precision and high-efficiency machines have been equipped with digital control devices or digital position indicators. In this case, the position detector is indispensable, it must have the following conditions: (1) high precision, no cumulative error; (2) performance changes over time with less stability and high reliability; (3) temperature and humidity Little influence;