Showing papers by "Takashi Tokuda published in 2005"

Flexible and extendible neural interface device based on cooperative multi-chip CMOS LSI architecture

Abstract: An LSI-based cooperative multi-chip neural interface device, for stimulation as well as recording, is proposed and fabricated. The proposed multi-chip device consists of small (600 μm × 600 μm in the present design) intelligent neural interface unit chips. The unit chip has nine neural stimulation/recording electrodes and an individual control circuit. It can work not only as a stand-alone unit, but also in cooperation with other unit chips. One can configure any number of the unit chips as a multi-chip neural interface device. Compared to conventional single-chip architecture, the proposed multi-chip architecture has a number of advantages including thinness, mechanical strength, flexibility, and extendibility. That makes the multi-chip neural interface device more suitable for in vivo applications than conventional single-chip devices. Packaging technology for the multi-chip device was also developed. We developed a thin, flexible packaging technique for the multi-chip neural interface device and LSI-compatible Pt/Au stacked bump electrodes. The functions of the fabricated multi-chip neural interface device were characterized and the feasibility of the device as a random-access, multi-site stimulator was demonstrated.

Eyesight regeneration supporting apparatus

Abstract: PROBLEM TO BE SOLVED: To provide an eyesight regeneration supporting apparatus which can suppress the scaling up of an apparatus installed in the body even when the number of electrodes becomes large and can efficiently execute the arrangement of the large number of the electrodes. SOLUTION: The eyesight regeneration supporting apparatus to regenerate the eyesight by applying the electrical stimulation to cells which form the retina is equipped with the two or more electrodes 27 which give electrical stimulation pulse signals to the cells which form the retina, a substrate 21 in which the electrodes are disposed, and two or more switching control units 24 which are disposed in the substrate and selectively switch the electrodes which output the electrical stimulation pulse signals, wherein it is so constituted that the two or more electrodes form two or more groups by being divided into the prescribed number and one switching control unit is connected to each the group. COPYRIGHT: (C)2007,JPO&INPIT

Pulse modulation CMOS image sensor for bio-fluorescence imaging applications

Abstract: For wide dynamic range, compatibility with digital circuits, and low-voltage operation, the pulse modulation technique is suitable for an implanted bioimage sensor. We demonstrate bio-fluorescence imaging of the hippocampus in a sliced mouse brain using a pulse modulation-based image sensor. The sensor architecture and system configuration are discussed. In addition, we develop an imaging device for implantation into a mouse brain in order to measure the neural activity in the hippocampus. The device is composed of a pulse modulation image sensor with 128/spl times/128 pixels and a fiber illuminator on a polyimide substrate.

Micro-sized photo-detecting stimulator array for retinal prosthesis by distributed sensor network approach

Abstract: In this paper, we propose a flexible retinal prosthetic device using a distributed sensor network. The novel point of the proposed device is that the flexible stimulator consists of micro-sized CMOS devices linked in a network. In the micro-sized CMOS device single-wire serial interface, a photosensor with a pixel-level analog-to-digital converter (ADC), an image processing circuit, and a current driver circuit are integrated. The device is fabricated using 0.6 μm CMOS technology with a size of 500 μm × 500 μm. We present the results of a successful test of a prototype device.

Flexible and extendible neural stimulation device with distributed multichip architecture for retinal prosthesis

Abstract: We have proposed and designed a flexible and extendible neural stimulation device based on a distributed multichip architecture. The device is intended for retinal prosthesis application. A 4×4 array of small (600 µm×600 µm) unit chips was designed and fabricated with 0.6 µm standard complementary metal-oxide semiconductor (CMOS) technology. A package technology for a flexible retinal stimulation device has also been developed. We have demonstrated the function and feasibility of the device as a retinal stimulator in a saline environment.

Retinal prosthesis device based on pulse-frequency-modulation vision chip

Abstract: We describe a retinal prosthesis device that uses an image sensor based on a pulse frequency modulation (PFM) photosensor array. A PFM-based photosensor converts light intensity into the frequency of an output electrical pulse stream, and thus is suitable for stimulating retinal cells. We demonstrate various circuit improvements for image preprocessing and packaging techniques and present the results of an electrophysiology experiment.

A CMOS optical/potential image sensor with 7.5μm pixel size for on-chip neural and DNA spot sensing

Abstract: An optical/potential CMOS image sensor was designed and fabricated for bioimaging applications. The image sensor is capable to simultaneously sense an optical image and an on-chip potential image. Target applications of the sensor are on-chip (optical + potential) neural imaging and on-chip DNA microarray sensing. The sensor has a QCIF (176 times 144) pixel array with alternatively aligned optical/potential sensing pixels. The pixel size is 7.5 mum times 7.5 mum. The potential resolution is confirmed to be better than 10 mV. An on-chip fluorescence imaging of a mouse's hippocampus was performed to demonstrate that fluorescence imaging is possible with on-chip configuration

Pulse modulation image sensors for on-chip bioimaging and biosensing applications

Abstract: Image sensors with pulse modulation measurement scheme are fabricated for bioimaging and biosensing ap-plications. We designed pulse modulation photosensors, a 64×64-pixels image sensor for in vitro bioimaging, and a 176×144-pixels (QCIF) image sensor for in vivo bioimaging. We demonstrated the feasibility of the pulse modulation measurement scheme for biosensing applications. We obtained a dynamic range of 120dB and minimum sensing intensity level of 2nW/cm 2 . We also confirmed that 0.2% of intensity change is detectable at the minimum intensity region. An in vitro, on-chip imaging of a mouse hippocampus was successfully demonstrated. A sensor module for in vivo imaging is also developed.