Tsuyoshi Iwamoto

Linear-logarithmic image sensor with low noise and no flickers

This paper proposes and demonstrates a linear-logarithmic image sensor that can operate in both the linear and logarithmic modes, and exhibits low noise and no flickers. Its pixel is composed of one buried-photodiode, five n-channel MOS transistors, two p-channel MOS transistors, and one capacitor. During the linear mode operation, the pixel behaves the same as the four-transistor one, offering a low dark current and low noise. Also, in the logarithmic mode, it operates in an integrating manner in contrast to the majority of logarithmic-response CMOS image sensors that operate in a continuous manner. Thus it has no flickers and can calibrate the fixed pattern noise using the reference level. A wide dynamic range of 190 dB has been confirmed with a 256 × 256-pixel image sensor employing this novel pixel architecture.

Development of hybrid multibeam module using polymer waveguides for laser scanning optics

A hybrid multibeam module using optical waveguides has been developed for laser scanning optics. The module is constructed using hybrid electrical/optical integration technology. Waveguides and laser diodes are assembled on a silicon substrate on which emitted beams from the laser diodes are coupled into waveguides. For the shorter 780 nm wavelength, which is used for this module, the precision of position control for laser diodes and waveguides must improve below 1 micrometers . The polyimide waveguides, which are suitable for mass production, are used. It is confirmed that the multibeam module consisting of a beam divergence angle from 10 degrees to 20 degrees, spatial beam interval with a 12-micrometers minimum, and a large number of the beams is possible.