3第三章CCD课案.ppt

第二层是“分色滤色片”(单CCD) CCD芯片将光子转换为电子，在这一过程当中，光子数目与电子数目互成比例。 光子还有另外一个特征值——波长。但这条信息却没有被转换为电子。 因此CCD芯片都可以被称为色盲。 Structure of a CCD 3. One pixel Channel stops to define the columns of the image Transparent horizontal electrodes to define the pixels vertically. Also used to transfer the charge during readout Plan View Cross section The diagram shows a small section (a few pixels) of the image area of a CCD. This pattern is reapeated. Electrode Insulating oxide n-type silicon p-type silicon Every third electrode is connected together. Bus wires running down the edge of the chip make the connection. The channel stops are formed from high concentrations of Boron in the silicon. Structure of a CCD 4. On-chip amplifier at end of the serial register Cross section of serial register Image Area Serial Register Once again every third electrode is in the serial register connected together. Below the image area (the area containing the horizontal electrodes) is the ‘Serial register’ . This also consists of a group of small surface electrodes. There are three electrodes for every column of the image area Structure of a CCD 5. The serial register is bent double to move the output amplifier away from the edge of the chip. This useful if the CCD is to be used as part of a mosaic.The arrows indicate how charge is transferred through the device. Edge of Silicon 160mm Image Area Serial Register Read Out Amplifier Bus wires Photomicrograph of a corner of an EEV CCD. Structure of a CCD 6. OD OS RD R SW Output Node Substrate Output Transistor Reset Transistor Summing Well 20mm Output Drain (OD) Output Source (OS) Gate of Output Transistor Output Node R Reset Drain (RD) Summing Well (SW) Last few electrodes in Serial Register Serial Register Electrodes Photomicrograph of the on-chip amplifier of a Tektronix CCD and its circuit diagram. Electric Field in a CCD 1. The n-type layer contains an excess of electrons that diffuse into the p-layer. The p-layer contains an excess of h