Microelectronic stimulator array for stimulating nerve tissue
View Patent ↗The retinal prosthesis test device is comprised of a thin wafer of glass made from nanochannel glass (NGC) with very small channels perpendicular to the plane of the wafer filled with an electrical conductor forming microwires. One surface of the glass is ground to a spherical shape consistent with the radius of curvature of the inside of the retina. The NGC is hybridized to a silicon de-multiplexer and a video image is serially input to a narrow, flexible micro-cable and read into a 2-D array of unit cells in a pixel-by-pixel manner which samples the analog video input and stores the value as a charge on a MOS capacitor. After all unit cells have been loaded with the pixel values for the current frame, a biphasic pulse is sent to each unit cell which modulates the pulse in proportion to the pixel value stored therein. Because the biphasic pulses flow in parallel to each unit cell from a global external connection, the adjacent retinal neurons are all stimulated simultaneously, analogous to image photons stimulating photoreceptors in a normal retina. A permanent retinal implant device uses a NGC array hybridized to a silicon chip, the image is simultaneously generated within each cell through a photon-to-electron conversion using a silicon photodiode. The photons propagate directly through into the backside of the device. Electrical power and any control signals are transmitted through an inductively driven coil or antenna on the chip. The device collects the charge in storage capacitors via the photon-to-electron conversion process, stimulates the neural tissue with biphasic pulses in proportion to the stored charges, and resets the storage capacitors to repeat the process.
1. A retinal prosthesis test device comprised of:
an external image source producing a video image;
a micro-cable for conducting the video through a patient's eye wall;
an electronic chip for demultiplexing the video image into a two-dimensional (2-D) array of unit cells;
a nanochannel glass electrode array hybridized to said 2-D array of unit cells with induim bumps and electrically connecting each unit cell to adjacent neural tissue;
an external electronic circuit board generating a biphasic pulse applied globally to the unit cells through the micro-cable causing an electronic signal to be directed into a human eye retina wherein it is converted to an electrochemical signal and transmitted within the eye to a patient's optic nerve,
whereby said device stimulates neural tissue via a conformal surface achieved by machining said nanochannel glass surface.
2. A device, as in claim 1 , wherein the nanochannel glass electronic array is comprised of a hybridized to the microelectronic chip mounted on a ceramic chip carrier, all unit cells controlled by a series of row shift registers and column shift registers for directing the incoming video image to a predetermined unit cell.
3. A permanent retinal implant device comprised of:
a nanochannel glass electrode array and thinned electronic chip for receiving photons through a human iris and converting said photons to a two-dimensional (2-D) spatially discrete electrical signal residing in individual unit cells;
an electronic unit located externally on a patient for inductively transmitting electrical power and control signals to the electronic chip and nanochannel glass electrode array within the patients eye;
a biphasic pulse generated with on-chip electronic circuitry causing an electrical signal to be routed through the nanochannel glass electrode array and applied to adjacent retinal tissue in a human eye where it is converted into an electrochemical signal to be transmitted through retinal neurons within the eye to a patients optic nerve;
whereby said device stimulates neural tissue via a conformal surface achieved by machining said nanochannel glass surface.
4. A device, as in claim 3 , wherein the nanochannel glass electronic array is further comprised of an on-chip antenna for receiving the inductively transmitted signals and applying them selectively to an array of unit cells, digital electronics for controlling the application of the electrical to the retinal tissue, an on-chip power receiver for applying power to the array of unit cells, a bias voltage supply for operating the electronic chip, and a biphasic pulse generator for generating the biphasic pulse, as well as row and column shift registers.