Enzyme linked-immunosorbent assay (ELISA) is a diagnosis method used for early stage cancers and other diseases. Recently, digital ELISA has been proposed to achieve higher sensitivity. In order to distribute the diagnosis system widely in clinical practice, we have proposed a compact observation system. In the system, fluorescence microscope was replaced by CMOS image sensor, which can realize palmtop equipment. The properties of CMOS image sensor and fluorescence filter should be optimized for the system. We simulated the characteristics of micro pillar absorption filter surrounded by metal, which can effectively transmit fluorescence from reaction chambers to photodiodes of CMOS image sensor.
