Newark, NJ—Panasonic Corporation has developed a new technology in image sensors. The breakthrough is the electrical control of the near infrared (NIR) light sensitivity of the same pixel in an organic CMOS image sensor. Among other benefits, the new technology will contribute to the development of more compact camera systems.
The sensitivity of the pixels in the sensor is simultaneously controlled by changing the applied voltage to the organic films. Additionally, the sensor has directly stacked organic film. The new technology is said to enable switching between modes of color imaging and NIR imaging frame by frame without a mechanical IR cut filter required with conventional sensors.
This development will contribute to miniaturizing camera systems. The technology will also enable global shutter operation. Therefore, it will be suitable for applications in fields where fast, accurate inspection or recognition is necessary. These applications include machine vision and intelligent transportation systems.
However, the primary advantage of the new technology, reports Panasonic, is that it facilitates frame-by-frame switching between the color imaging mode and NIR imaging mode without a loss of resolution.
Organic CMOS Technology Details
In the organic CMOS sensor, photoelectric conversion is executed by an organic film. Si-based circuits beneath this film execute the signal charge accumulation and the signal readout. With Panasonic’s new technology, the film and the circuits can be designed independently. This will allow the organic CMOS sensor to achieve several important features. These include high sensitivity, wide dynamic range, and global shutter function.
The newly developed technology also extends the spectral sensitivity of the image sensor from the visible light spectrum to the near infrared (NIR) light spectrum. Consequently, it makes it possible to control the NIR light sensitivity electrically without losing the unique features of organic CMOS sensors. This is possible because by stacking two organic layers, one can absorb visible light and the other NIR light. However, to distinguish the NIR light signal from visible light signal, Panasonic adopted the direct-stacked structure of two organic layers with a high resistance ratio.
Panasonic holds 94 Japanese patents and 68 overseas patents (including pending) related to these technologies. The company will present some part of these technologies at the international academic conference ISSCC 2017 (International Solid-State Circuit Conference). ISSCC is being held in San Francisco, California, February 5–9, 2017. panasonic.com