直接注入模式可见光和红外传感器的注入效率

Injection Efficiency of Direct Injection Mode Optical Sensors

固体成像传感器包括可见光CCD、IRCCD、CMOS和红外焦平面阵列,其信号由光电二极管经注入栅沟道直接输入到转移级是基本的注入模式。本文总结了近30年来的发展成果,阐述了直接注入效率的理论和基本公式,得出在取样频率低的情况下,增大注入栅的跨导和光电二极管的阻抗是提高注入效率的最有效方法;在光电二极管低阻抗的情况下,采用电流镜像直接注入新设计,其注入栅的跨导可趋于无限大,因而可使注入效率接近100%。分析了电路的新设计方法,研制了64元线列InSb电流镜像直接注入电路。初步测试表明,注入效率与理论分析接近。

There are several kinds of solid state ironing sensors such as visible CCDs, IRCCDs, CMOS and infrared focal plane arrays （IRFPA）. Their basic injection mode is that the signal is transported directly from a photodiode to a transition area via an injection channel. The research and development of direct injection techniques over the past 30 years are summarized. The theory and basic formulas of the direct injection mode of visible and infrared imaging sensors are analyzed. The result shows that the increase of the transconductance of an input gate and the impedance of a photodiode is the most effective method to improve injection efficiency when the sampling frequency is low. The transconductance of an input gate can become infinite by using a new current mirroring direct injection circuit when the impedance of a photodiode is low, and hence the injection efficiency can be close to 100%. The new circuit design method is analyzed. A direct injection circuit with a 64-element InSb linear array is developed. The preliminary test indicates that its injection efficiency is close to that of the theoretic analysis.