At EI2006, we proposed the CMOS image sensor, which was overlaid with organic photoconductive layers in
order to incorporate in it large light-capturing ability of a color film owing to its multiple-layer structure, and
demonstrated the pictures taken by the trial product of the proposed CMOS image sensor overlaid with an organic layer
having green sensitivity. In this study, we have tried to get the optimized spectral sensitivity for the proposed CMOS
image sensor by means of the simulation to minimize the color difference between the original Macbeth chart and its
reproduction with the spectral sensitivity of the sensor as a parameter. As a result, it has been confirmed that the
proposed CMOS image sensor with multiple-layer structure possesses high potential capability in terms of imagecapturing
efficiency when it is provided with the optimized spectral sensitivity.
Digital still cameras overtook film cameras in Japanese market in 2000 in terms of sales volume owing to their versatile functions. However, the image-capturing capabilities such as sensitivity and latitude of color films are still superior to those of digital image sensors. In this paper, we attribute the cause for the high performance of color films to their multi-layered structure, and propose the solid-state image sensors with stacked organic photoconductive layers having narrow absorption bands on CMOS read-out circuits.
A new structure CCD sensor has been developed, which can be improved in the image quality compared with the conventional Inter-line Transfer type CCD sensors. The image sensor used in a high-definition image capturing system like a DS camera has been improved to have more number of pixels. This pixel increase adversely affects the sensitivity, dynamic range, signal-to-noise (S/N) ratios. The new CCD sensor has a new pixel arrangement of a half-pitch offset and a new structure of the transfer electrodes, and it achieves to increase sensitivity, dynamic range, S/N and the image quality. The new signal processing system combined with this new CCD has been also developed. It includes high quality analog and digital signal processing LSIs. The newly developed digital signal processing combined with over-sampling technologies enables to achieve higher resolution than conventional cameras with the same number of pixels. The outlines of the new CCD and the signal processing system, the configuration, operations, and the experimental results are described.