一篇介绍自动调焦用于生物显微镜的英文章，包括其总体结构。-The bioengineering is a popular and fast-developing researching topic in recent years. Among them, the observation of microorganism is a very important experimental approach of bioengineering. As the biological sensing chip technology becomes mature, it is even beneficial to the research. Most of the biological sensing chips for measuring and observation adopt different type of precise microscopes and the corresponding software.