Japan's NHK Science & Technology Research Laboratories (STRL) is developing a small color camera with a single-chip color image sensor that uses stacked organic films. STRL fabricated a high-definition sensor by increasing the number of pixels and reducing the pixel size.
According to Tech-On the ultimate goal of NHK is to develop an ultra-small camcorder for super high vision. The company has been developing the organic image sensor for several years, but this is the first time that it has realized a shooting system using RGB color devices stacked together and substantiated the original concept, STRL said.
The camcorder equipped with the image sensor
The organic image sensor is a single-chip color image sensor with three layers of organic film, each sensitive to only one of the three primary color components of light. The layers are stacked with three transparent thin-film transistor circuits that read out signals from each film.
Each organic film absorbs light of only one of the three primary color components and converts it into an electric signal. The light of the other colors passes through to the layers below. The resulting single chip color image sensor has the same characteristics as a three-chip color image sensor that uses a prism.
They made progress in miniaturizing transparent TFT circuits and reduced the pixel pitch to 100μm, or one-sixth of the size the predecessor. The number of pixels was increased by more than eight times, to 12,200 pixels (128 horizontal x 96 vertical). They plan to increase the concentration of transparent TFT circuits to make an organic image sensor with even higher resolution.
STRK are working with Kochi University of Technology and Saitama University on the project.
Color camera imaging system
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