著者

Akihiro Uehara Keiichiro Kagawa Takashi Tokuda Jun Ohta Masahiro Nunoshita

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE Electronics Express (ISSN:13492543)

巻号頁・発行日

vol.1, no.18, pp.556-561, 2004 (Released:2004-12-25)

参考文献数

8

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A high-sensitive CMOS photosensor based on a pulse frequency modulation (PFM) scheme is presented. We propose and demonstrate the high-sensitive PFM photosensor, whose output frequency is proportionate to the incident light intensity, that utilizes MOS interface-trap charge pumping (ITCP) as a frequency-controlled ultra-low current. The proposed pixel sensor consists of only 4 transistors: a transistor as an ultra-low current source; a sense amplifier transistor; a selection transistor; and, a reset transistor. The prototype device is fabricated using 0.6-µm standard CMOS technology. High sensitivity 4.0 × 105Hz/(W·m-2), which is larger than two orders of magnitude compared to previous works, was obtained.

著者

Kaita Imai Keita Yasutomi Keiichiro Kagawa Shoji Kawahito

出版者

一般社団法人 電子情報通信学会

雑誌

IEICE Electronics Express (ISSN:13492543)

巻号頁・発行日

vol.9, no.24, pp.1893-1899, 2012-12-28 (Released:2012-12-28)

参考文献数

4

被引用文献数

2

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This paper proposes a distributed ramp signal generator of column-parallel single-slope ADCs for CMOS image sensors. This architecture does not require any power-hungry amplifiers of the conventional one but consists of miniaturized column-wise ramp signal generators connected together by metal wires, which achieves high linearity and high uniformity. Simulation results show less than 1LSB nonlinear error of the ramp signal at 12-bit ADC resolution is attained only by having the consumption current of 6.4mA and the area of 2.4mm2 which are much smaller than the conventional one. It is also confirmed that 100mΩ resistive connection attains less than 1LSB gain error mismatching, even though the mismatch of the column-wise ramp signal generators is as large as 20%.

著者

Keiichiro Kagawa

出版者

The Institute of Image Information and Television Engineers

雑誌

ITE Transactions on Media Technology and Applications (ISSN:21867364)

巻号頁・発行日

vol.9, no.2, pp.114-121, 2021 (Released:2021-04-01)

参考文献数

31

被引用文献数

4

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Multi-tap CMOS pixels that are composed of a single photodiode, multiple sets of a charge transfer gate and storage diode, and a draining gate can implement functional imaging. In this paper, imaging systems based on the multi-tap CMOS pixel are categorized into those with synchronized active illuminations and those using coded exposure. Applications for quantitative wide-field imaging based on spatial frequency domain imaging (SFDI) using structured light projection and multi-exposure laser speckle contrast blood flow imaging (MELSCI) utilizing multiple exposure times are shown. The multi-tap CMOS pixel provides additional benefits like suppression of ambient light and motion artifact with SFDI and efficient sampling at a video rate with MELSCI.