Purchase this article with an account.
Douglas B. Shire, Tom Salzer, William Jones, Ali Karbasi, Sonny Behan, William A. Drohan, Oscar Mendoza, Jinghua Chen, John Wyatt, Joseph F. Rizzo, III; Hermetic Sealing and Packaging Technology for the Boston Retinal Prosthesis. Invest. Ophthalmol. Vis. Sci. 2012;53(14):5523. doi: https://doi.org/.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
This work is related to the efforts of the Boston Retinal Implant Project to develop a sub-retinal prosthesis to restore vision to the blind. This poster focuses on high density packaging advancements for the Boston prosthesis, especially hermetic sealing processes for the exterior of the packages.
Two-piece custom-machined titanium micro-enclosures 11mm in diameter were sealed using two methods. In the first, the clam shell-like parts were laser welded, and in the second, the parts were sealed by projection welding. Cofired ceramic structures with Pt signal feedthroughs were also fabricated to mate with these structures, and were gold brazed to the miniature titanium housings. In a subsequent assembly step, flexible stimulating sub-retinal iridium oxide electrode arrays were joined to the feedthrough assemblies by thermo-compression bonding.
Tests of the retinal implant assemblies' quality were performed using x-ray analysis, helium leak testing, high pressure burst testing, and precision metallography of the welded joints. In the Figure, a cross section of a projection-welded implant assembly showing normal Ti grain structure is shown. Additionally, the thermo-compression bonds to the prosthesis' electrode array had an average shear strength of more than 50 grams force, indicating good quality bonding. Helium leak rates better than 1.0x10E-09 standard cc He / second were obtained. The resulting assemblies had specialized suture arms attached and were subsequently implanted in Yucatan mini-pig animal models.
The feasibility of high-quality bonding and hermetic sealing of miniature titanium implantable retinal prosthesis assemblies has been demonstrated, and microfabricated electrode arrays having 256+ channels were successfully bonded to the package exterior. These structures will be key components in the next-generation high-density Boston retinal prosthesis.
This PDF is available to Subscribers Only