Improved near-infrared sensitivity of CCD image sensors

This enhanced sensitivity can be critical in applications such as scientific and medical imaging, where samples emit or fluoresce in NIR wavelengths; or in machine vision and intelligent transportation systems, where NIR illumination is often used to better examine an object or to isolate a vehicle’s license plate.

The CCD pixel design used in the KAI-08052 extends the electron capture region deeper in the silicon to better capture electrons generated by long wavelength photons. This deeper pixel well improves detection of NIR wavelengths by up to a factor of two depending on the specific wavelength studied.  And since the well structure also isolates the photodiodes from each other, this increase in NIR sensitivity comes without any reduction in image sharpness (Modulation Transfer Function, or MTF).

Herb Erhardt, Vice President and General Manager, Industrial and Security Division, Image Sensor Group, ON Semiconductor, commented: “Camera manufacturers and end customers continue to confirm that products based on both CCD and CMOS technologies will be needed in these markets, making it important that we continue to develop and advance both of these technologies. The KAI-08052 provides a significant improvement in NIR sensitivity compared to our standard pixel design, and we look forward to utilising this technology in additional products in the future.”

The KAI-08052 is available in a RoHS-compliant CPGA-67 package in Monochrome, Bayer Colour and Sparse Colour configurations, and is fully pin compatible with the existing KAI-08051 image sensor as well as a full family of 5.5 and 7.4µm CCD image sensors, enabling camera manufacturers to quickly adopt the new device.