semiconductor curve tracer for image sensor research

艾伯塔大学的成像科学实验室正在开发一种用于图像传感器的“压扩”结构，并需要半导体曲线跟踪器来实现。在压缩图像传感器中，像素对光刺激的响应并不直接与入射照度成正比，而是取决于负载晶体管的非线性特性，负载晶体管压缩信号的方式与人眼的压缩方式大致相同。一旦信号从模拟域转换到数字域，它就被再次扩展，以便可以正确地显示颜色信息。压缩-扩展或压扩结构的优势在于，它通过利用晶体管的大信号或本征特性实现高对比度和高速成像。成像科学实验室认为，随着技术的发展，这种方法将挑战传统的图像传感器。随着微电子器件变得越来越小，在模拟域获得线性响应变得更加困难，而数字域对信号处理变得更加有效。压扩结构的成功开发，特别是自校准能力，取决于对组成图像传感器的二极管和晶体管中的电流-电压(I-V)关系的良好理解。这些I-V曲线在图像传感器上的变化，以及从一个图像传感器到另一个图像传感器，与平均曲线一样重要。半导体曲线示踪剂将有助于研究这些关系。最后，同样在阿尔伯塔大学的超大规模集成电路实验室将利用曲线示踪器研究微流控芯片的集成电子学，这些芯片在医疗保健和诊断方面有应用。

The Imaging Science Lab at the University of Alberta is developing a "companding" architecture for image sensors and requires a semiconductor curve tracer to do so. In a companding image sensor, the response of a pixel to a light stimulus is not directly proportional to the incident illuminance but depends on the nonlinear characteristic of a load transistor, which compresses the signal in much the same way as the human eye. Once the signal is converted from the analog to the digital domain, it is expanded again so that colour information may be displayed properly. Advantages of the compressing-expanding, or companding, architecture are that it enables high contrast and high speed imaging by exploiting the large-signal or native properties of transistors. The Imaging Science Lab believes this approach will challenge conventional image sensors as technology scales. As microelectronic devices get smaller, it becomes more difficult to obtain linear responses in the analog domain anyway and the digital domain becomes more efficient for signal processing. The successful development of the companding architecture, especially an ability to self-calibrate, depends on a good understanding of current-voltage (I-V) relationships in the diodes and transistors that make up the image sensor. The variation in these I-V curves across an image sensor, and from one image sensor to another, are just as important as the average curve. A semiconductor curve tracer will help to study these relationships. Finally, the VLSI Lab, also at the University of Alberta, will make use of the curve tracer in its research on integrated electronics for microfluidic chips, which have applications in health care and diagnostics.