High resolution tri-linear colour TDI CCD image sensor with programmable responsivity gain

摘要

We developed a 6032 element, 32 stage Tri-linear Time Delay and Integration Focal Plane Array for high resolution colour imaging applications. The sensor offers an improvement of a factor of 10 over comparable line scan CCD sensors. The imager architecture utilizes three individual TDI arrays, with a new multi-layer dielectric interference film (DIF) color filter or a dyed polyamide patterned monolithic filter that helps achieve accurate spectral separation in the three primary colour bands centered at 450 nm, 550 nm and 650 nm respectively. We also incorporated in the sensor a new programmable responsivity mechanism. This is achieved by an on-chip imaging area size selection mechanism. The sensors operate in the time-delay-and-integration mode. Depending on the level of illumination the user is able to dynamically select the number of TDI stages per sensor. The total number of TDI gain stages can be selected in blocks of 32, 16, 8, or 4. This property provides improvement in the dynamic range of the sensor by extending the response of the CCD over a wide range of illumination levels. Depending on the light energy incident on the sensor, the user can dynamically vary the number of TDI stages used for integrating an incident scene. The result is a programmable responsivity depending on the level of incident illumination. Such technique optimizes the performance of the CCD colour sensor.