Akihiro Uehara

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In this presentation, we demonstrate a pulse-frequency-modulation (PFM)-based retinal stimulator for sub-retinal implantation using standard CMOS technology with low voltage operation of 1.2 V. A PFM-based photosensor converts input light intensity to electrical pulse trains whose frequency is proportional to the input light intensity. To employ simple(More)
This paper proposes and demonstrates novel types of vision chips that utilize pulse trains for image processing. Two types of chips were designed using 1.2 µm double-metal double-poly CMOS process; one is based on a pulse width modulation (PWM) and the other is based on a pulse frequency modulation (PFM). In both chips the interaction between the pixels(More)
This paper describes a retinal prosthetic device using a pulse frequency modulation (PFM) based photosensor with a standard CMOS technology and its modification to stimulate retinal cells effectively. A 32x32-pixel PFM photosensor array chip have been fabricated using 0.6 μm CMOS technology and demonstrated the improved functions.
We propose a CMOS vision chip, an image sensor with pixel-level signal processing, to serve as a replacement for degenerated photoreceptor cells in the retina. In our approach, a vision chip is implanted underneath the retina (the subretinal space). For efficient electric stimulation, we utilize a pulse frequency modulation (PFM). Each pixel consists of a(More)