Pulse-frequency-modulation vision chip with frequency range control as a retinal prosthesis device

Tetsuo Furumiya; Akihiro Uehara; Keiichi Isakari; Norikatsu Yoshida; Keiichiro Kagawa; Jun Ohta; Masahiro Nunoshita

doi:10.1117/12.527528

19 November 2003 Pulse-frequency-modulation vision chip with frequency range control as a retinal prosthesis device

Tetsuo Furumiya, Akihiro Uehara, Keiichi Isakari, Norikatsu Yoshida, Keiichiro Kagawa, Jun Ohta, Masahiro Nunoshita

Proceedings Volume 4829, 19th Congress of the International Commission for Optics: Optics for the Quality of Life; (2003) https://doi.org/10.1117/12.527528
Event: 19th Congress of the International Commission for Optics: Optics for the Quality of Life, 2002, Florence, Italy

Abstract

In this paper, we propose and demonstrate a new pixel structure of a vision chip for visual recovery of the blind by means of electric stimulation against the retina. We introduce output frequency range control to a conventional pulse frequency modulation (PFM) photosensor. To configure the lower and upper limits of the output pulse frequency suitable for electric stimulation, we added nMOS and pMOS leak transistors and a switched-capacitor filter to an original PFM pixel circuit. We fabricated a test circuit of the improved PFM pixel using a standard 0.6 μm CMOS process. The pulse frequency range was successfully fixed, for example, from 100 Hz to 1 kHz.

Citation Download Citation

Tetsuo Furumiya, Akihiro Uehara, Keiichi Isakari, Norikatsu Yoshida, Keiichiro Kagawa, Jun Ohta, and Masahiro Nunoshita "Pulse-frequency-modulation vision chip with frequency range control as a retinal prosthesis device", Proc. SPIE 4829, 19th Congress of the International Commission for Optics: Optics for the Quality of Life, (19 November 2003); https://doi.org/10.1117/12.527528

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