Retinal prostheses
Optoelectronic retinal prostheses transduce light into electrical current for neural stimulation. A novel optoelectronic pixel architecture is presented comprising a vertically integrated photo junction field-effect-transistor (Photo-JFET) and neural stimulating electrode. Experimental measurements demonstrate that optically addressed Photo-JFET pixels utilize phototransistive gain to produce a broad range of neural stimulation current and can effectively stimulate retinal neurons in vitro. The compact nature of the Photo-JFET pixel can enable high resolution retinal prostheses with a theoretical visual acuity ˜20/60 to help restore vision in patients with degenerative retinal diseases.
1. A retinal prosthesis, comprising:
a vertically integrated photosensitive junction field-effect-transistor (Photo-JFET) etched from a silicon substrate doped to form a stack of N—P—N or P—N—P layers, forming a silicon mesa pillar and having an outer wall which is coated with a dielectric layer of SiO2, which induces an inversion layer along a vertical direction on the outer wall of the silicon mesa; and
a neural stimulating electrode.
2. The retinal prosthesis in claim 1 , wherein the Photo-JFET includes a photodetector.
3. The retinal prosthesis in claim 1 , wherein the Photo-JFET includes an amplifier.
4. The retinal prosthesis in claim 1 , wherein the Photo-JFET includes a neural electrode stimulator.
5. The retinal prosthesis in claim 1 , wherein the Photo-JFET includes a silicon pixel mesa.
6. The retinal prosthesis in claim 5 , wherein the silicon pixel mesa further includes a photodetector.
7. The retinal prosthesis in claim 6 , wherein the silicon pixel mesa further includes an amplifier.
8. The retinal prosthesis in claim 7 , wherein the silicon pixel mesa further includes a neural electrode stimulator.
9. The retinal prosthesis in claim 8 , further comprising a dielectric film positioned on the silicon pixel mesa.
10. The retinal prosthesis in claim 1 , wherein a current range of 0.1-100 μA is produced by the retinal prosthesis when illuminated with near infrared light at an irradiance of 0.01-5 mW/mm 2 .
11. The retinal prosthesis in claim 1 , further comprising a 13 μm pixel.
12. The retinal prosthesis in claim 1 , further comprising an array of 13 μm pixels.
13. The retinal prosthesis in claim 1 , further comprising a 40 μm pixel.
14. The retinal prosthesis in claim 1 , further comprising an array of 40 μm pixels.
15. The retinal prosthesis in claim 1 , further comprising a pair of back-to-back p/n diodes.
16. The retinal prosthesis in claim 15 , wherein the diodes are configured in a N—P—N configuration.
17. The retinal prosthesis in claim 15 , wherein the diodes are configured in a P—N—P configuration.
18. A retinal prosthesis, comprising:
a vertically integrated photosensitive junction field-effect-transistor (Photo-JFET) etched from a silicon substrate doped to form a stack of N—P—N or P—N—P layers, forming a silicon mesa pillar and having an outer wall which is coated with a dielectric layer of SiO2, which induces an inversion layer along a vertical direction on the outer wall of the silicon mesa; and
a neural stimulating electrode;
wherein a current range of 0.1-100 μA is produced when illuminated with near infrared light at an irradiance of 0.01-5 mW/mm 2 .
19. A retinal prosthesis, comprising:
a vertically integrated photosensitive junction field-effect-transistor (Photo-JFET) having a pixel size range of 1-100 μm and etched from a silicon substrate doped to form a stack of N—P—N or P—N—P layers, forming a silicon mesa pillar and having an outer wall which is coated with a dielectric layer of SiO2, which induces an inversion layer along a vertical direction on the outer wall of the silicon mesa; and
a neural stimulating electrode.
20. The retinal prosthesis in claim 19 , further comprising an array of pixel size range of 1-100 μm.