Plasma-coupled bipolar linear image sensor

A new bipolar 1728-bit linear image sensor is described. Combining the plasma-coupled device (PCD) shift registers and a photodiode array, a simple structure and unique operation are realized. In contrast to other MOS or CCD imaging devices, some remarkable characteristics and performance were obtained. High output power, more than 1 mW, and high sensitivity of 2.26 × 10⁸µA/µJ (at 6000 Å) were measured. Spectra response is observed from 0.45 µm to 0.95 µm, and lineaxity is about unity. Large ratio, more than 46 dB, is easily attained. Inherent thermal noise, induced spike noise, and transfer noise axe less than in other conventional imaging devices. Only a single power supply of less than +5 V is necessary. A wide scanning clock frequency range from dc to 3 MHz can be used with a power dissipation of 70 mW being obtained. The above features are discussed in terms of a theory based on the low impedance nature of the bipolar sensing circuit.