小机芯离焦检测系统特性的新型测量方法

A New Measurement Method of the Traverse Focus Error Detection System

利用聚焦预搜索原理,测量出小机芯离焦检测系统特性的关键参数:离焦偏置、离焦灵敏度和线性区范围。首先将周期电压输入小机芯的聚焦力矩器使小机芯进行聚焦预搜索,同时得到聚焦误差曲线;然后根据聚焦误差曲线计算出小机芯离焦检测系统的特性,利用聚焦误差曲线S状脉冲的出现时刻计算出离焦偏置,利用S状脉冲的斜率和峰峰值得到离焦灵敏度和线性区范围;最后给出测量实例。该方法采用电信号测量小机芯的离焦检测系统特性,无需进一步的聚焦闭环控制以及三维精密工作台,具有设备简单、易于实现等特点。

Based on the focus pre-search a method is presented to measure the characteristics of the traverse focus error detection system ：focus offset ,focus error sensitivity and linear range. A periodical input voltage to focus actuator makes the traverse to do pre-search and the focus error signal is generated. Then from the focus error signal the traverse focus offset is calculated by the focus error occurring time ,and the traverse focus error sensitivity and linear range are calculated by the focus error slope and peak-to-peak value. A traverse focus error detection system is measured. The method uses electric signal to measure the characteristics of the traverse focus error detection system, and doesnot need the close loop control and the three dimensional platform,and is easy to realize.