日本电信电话公司研制了用光测量电机的转数和试料台微动距离的超小型编码装置(位置检测装置)、其大小程度低于1mm以下,测量移动量精度可达0.01μm,用半导体激光器和微小透镜、光电二极管等在测量方面所需要的部件全部在基板上集成,能 Nippon Telegraph and Telephone Corporation has developed an ultra-compact encoding device (position detection device) that measures the number of revolutions of the motor and the fretting distance of the sample stage by light, the magnitude of which is less than 1 mm, the accuracy of measurement of the amount of movement is 0.01 μm, Components required for measurement, such as lasers and tiny lenses, and photodiodes, are all integrated on the substrate.