压电双晶片扫描器的低温迟滞蠕变特性

Cryogenic hysteresis and creep characteristics of piezoelectric bimorph scanner

研究了用于空间红外相机低温光学系统的压电双晶片扫描器的低温迟滞蠕变问题。压电双晶片具有行程大,不发热,在低温下仍然能够工作等优点,然而由于压电陶瓷固有的迟滞蠕变特性,使得其扫描精度受到了较大的影响。本文在常温和低温下,对所研制的压电双晶片扫描器的迟滞和蠕变特性进行实验研究和特性对比。结果显示:尽管压电双晶片扫描器的迟滞量和蠕变量均有大幅度下降,但由于总行程的下降幅度更大,使得迟滞度和蠕变系数有较大上升;120K下的迟滞度约为300K下的2倍,120K下的蠕变系数比300K下的上升了一个数量级。低温下压电双晶片扫描器的迟滞和蠕变特性相比常温下更加严重,这给其在低温下的高精度应用带来了更大的影响。

The cryogenic hysteresis and creep characteristics of piezoelectric bimorph scanners for cryogenic optical systems in space infrared cameras were studied.The piezoelectric bimorph has superior characteristics of large displacement,high resolution,no self-heating,etc.,moreover,it can work efficiently at a cryogenic temperature.However,the inherent hysteresis and creep characteristics of the piezoelectric bmorph have a large impact on the scanning accuracy when it is used for high precision scanning.In this paper,the hysteresis and creep characteristics of a fabricated piezoelectric bimorph scanner were experimentally studied at room temperature and cryogenic temperature and the results were compared.The results indicate that both hysteresis displacement and creep displacement of the piezoelectric bimorph scanner have a large decrease,but the decrease of total travel displacement is much larger,which leads the hysteresis rate and creep coefficient increase more large.The hysteresis rate at 120 K is twice that at 300 K and the creep coefficient at 120 K increases by an order of magnitude as compared with that at 300 K.Results mean that the hysteresis and creep characteristics of piezoelectric bimorph scanner at cryogenic temperature are more serious than it at room temperature,which will bring greater impact when it is used for high precision applications.