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History of Japanese Project of Artficial Vision
About Artificial Retina
Research Groups of Artificial Vision
Japanese Projects for Artificial Vision
Development of Surgical Techniques for Implantaion/Assessment of Biocompatibility
Development of Medium Size Animal Model
Functional Assesment/Neuroprotection
Functional analysis, in vitro, in vivo
Development of Electrode/Total System
Functional Evaluation and Neuroprotection
Projects for Artificial Vision


Nara Institute of Science and Technology
1. Over 1000-ch electrode array based on distributed network architecture
Our goal is to develop an electrode array with over 1000-ch. To achieve this, we are developing an intelligent electrode array employing distributed network architecture. The array consists of many micro-nodes based on Si- LSIs, each about 500 μm square. Each micro-node stimulates retinal cells as well as communicates with other micro-nodes in the network. The key features are::
- Mechanical flexibility: micro-sized LSI chips are placed in a distributed manner and are small so that the array can be bent. The device is able to be fitted to the eyeball tightly and thus effectively stimulates retinal cells.
- Reduce the number of electrical connections required between electrodes: inter-chip communication circuits can be accommodated in the micro-sized LSI chip, which helps to reduce electrical wiring between the micro-nodes.
- Improved reliability: the network-linked architecture implements a routing function which allows failure nodes to be avoided. The failure nodes are blocked and their function terminated.
Figure 1 demonstrates the concept of the distributed-network-linked stimulus electrode array. We are developing such architecture for application to STS for sub-retinal implantation.

2. Vision chips for sub-retinal implantation
To attain dense retinal stimulation in the future, we are developing retina prosthetic chips based on LSI technologies to be implanted in the subretinal space. Integrated with imaging circuits, these chips can electrically stimulate retinal cells as well as acquire images. LSI technologies provide integration of versatile functions such as bi-phasic pulse circuits and high-sensitivity imaging. Remaining issues in incorporating LSI technologies in retinal prosthetic devices are the establishment of bio-compatible packaging technologies applicable to standard LSIs.
Figure 2 shows one example of a chip we have developed based on a pulse-frequency-modulation photosensor, which is suitable for stimulating retinal cells. The chip has image preprocessing functions in the pulse domain.