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Proceedings Paper

Pulse-frequency-modulation vision chip with frequency range control as a retinal prosthesis device
Author(s): Tetsuo Furumiya; Akihiro Uehara; Keiichi Isakari; Norikatsu Yoshida; Keiichiro Kagawa; Jun Ohta; Masahiro Nunoshita
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Paper 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.

Paper Details

Date Published: 19 November 2003
PDF: 2 pages
Proc. SPIE 4829, 19th Congress of the International Commission for Optics: Optics for the Quality of Life, (19 November 2003); doi: 10.1117/12.527528
Show Author Affiliations
Tetsuo Furumiya, Nara Institute of Science and Technology (Japan)
Akihiro Uehara, Nara Institute of Science and Technology (Japan)
Keiichi Isakari, Nara Institute of Science and Technology (Japan)
Norikatsu Yoshida, Nara Institute of Science and Technology (Japan)
Keiichiro Kagawa, Nara Institute of Science and Technology (Japan)
Jun Ohta, Nara Institute of Science and Technology (Japan)
Masahiro Nunoshita, Nara Institute of Science and Technology (Japan)


Published in SPIE Proceedings Vol. 4829:
19th Congress of the International Commission for Optics: Optics for the Quality of Life
Giancarlo C. Righini; Anna Consortini, Editor(s)

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