Housing for a circuit that is to be implanted in-vivo and process of making the same

Abstract

The present invention provides a biocompatible circuit assembly that includes a circuit encased within a housing. In some embodiments, the housing is a PMMA housing and before the circuit is enclosed within the housing the circuit is encased within a brick of epoxy.

1 . A biocompatible, human implantable apparatus, comprising: 
 a fully enclosed housing; and    a circuit encased within a brick of epoxy,    wherein the brick of epoxy containing the circuit is housed in said housing.    
     
     
         2 . The apparatus of  claim 1 , wherein the housing is a polymer housing and the polymer is an organic polymer.  
     
     
         3 . The apparatus of  claim 2 , wherein the polymer housing comprises PMMA.  
     
     
         4 . The apparatus of  claim 2 , wherein the polymer housing consists of PMMA.  
     
     
         5 . The apparatus of  claim 2 , wherein the polymer housing consists essentially of PMMA.  
     
     
         6 . The apparatus of  claim 1 , wherein at least part of the circuit is covered with an epoxy including a light blocking pigment.  
     
     
         7 . The apparatus of  claim 6 , wherein the circuit comprises a substrate and a plurality of components attached to said substrate.  
     
     
         8 . The apparatus of  claim 1 , further comprising a glass tube, wherein the epoxy brick containing the circuit is positioned within said glass tube and said glass tube is housed within said housing.  
     
     
         9 . The apparatus of  claim 8 , wherein a glass ball is used to seal an open end of said glass tube.  
     
     
         10 . The apparatus of  claim 8 , wherein an optical epoxy fills spaces between said glass tube and the inner wall of said housing.  
     
     
         11 . The apparatus of  claim 8 , wherein an optical epoxy fills spaces between said circuit and the inner wall of said glass tube.  
     
     
         12 . The apparatus of  claim 1 , wherein the housing is substantially cylindrical in shape and has an inner diameter.  
     
     
         13 . The apparatus of  claim 12 , wherein the inner diameter of the polymer housing is equal or about equal to the square root of: (w 2 +h 2 ), where w is the width of the epoxy brick and h is the height of the epoxy brick.  
     
     
         14 . The apparatus of  claim 1 , wherein the housing does not comprise any glass.  
     
     
         15 . A biocompatible, human implantable apparatus, comprising: 
 a fully enclosed housing;    a glass housing housed within said housing, the glass housing comprising a glass tube having an open end and a glass ball sealing said open end of said tube; and    a circuit housed within said glass housing.    
     
     
         16 . The apparatus of  claim 15 , wherein the housing is a polymer housing and the polymer is an organic polymer.  
     
     
         17 . The apparatus of  claim 16 , wherein the polymer housing comprises PMMA.  
     
     
         18 . The apparatus of  claim 16 , wherein the polymer housing consists of PMMA.  
     
     
         19 . The apparatus of  claim 16 , wherein the polymer housing consists essentially of PMMA.  
     
     
         20 . The apparatus of  claim 15 , wherein at least part of the circuit is covered with an epoxy including a light blocking pigment.  
     
     
         21 . The apparatus of  claim 20 , wherein the circuit comprises a substrate and a plurality of components attached to said substrate.  
     
     
         22 . The apparatus of  claim 15 , further comprising optical epoxy, wherein the optical epoxy fills spaces between said glass housing and the inner wall of said housing.  
     
     
         23 . The apparatus of  claim 15 , wherein an optical epoxy fills spaces between said circuit and the inner wall of said glass housing.  
     
     
         24 . A method for fully encasing a circuit within a polymer housing, comprising: 
 placing the circuit in a mold;    injecting a formulation into the mold so that the formulation completely surrounds the circuit, wherein the formulation comprises monomers; and    polymerizing the monomers.    
     
     
         25 . The method of  claim 24 , further comprising the step of covering the circuit with an epoxy prior to placing the circuit in the mold, wherein a sufficient amount of epoxy is used to cover the circuit so that the resulting surface topology is substantially smooth.  
     
     
         26 . The method of  claim 24 , wherein the polymerization step is performed in a pressure vessel where the pressure is increased to at least about 125 psi using inert gas.  
     
     
         27 . The method of  claim 24 , wherein the formulation comprises MMA monomers.  
     
     
         28 . The method of  claim 27 , wherein the formulation further comprises pre-polymerized PMMA.  
     
     
         29 . The method of  claim 28 , wherein the formulation comprises between 60% and 80% pre-polymerized PMMA by volume.  
     
     
         30 . The method of  claim 24 , wherein the formulation consists essentially of MMA monomers.  
     
     
         31 . The method of  claim 24 , wherein the formulation consists of MMA monomers.  
     
     
         32 . A method for fully encasing a circuit within a housing, comprising: 
 inserting the circuit into the housing;    injecting an optical epoxy into the housing;    placing the housing containing the optical epoxy and the circuit into a pressure vessel;    increasing the pressure within the vessel;    increasing the temperature within the vessel;    allowing the optical epoxy to cure;    removing the housing from the pressure vessel; and    capping an open end of the housing.    
     
     
         33 . The method of  claim 32 , wherein the housing comprises PMMA.  
     
     
         34 . The method of  claim 32 , wherein the housing consists essentially of PMMA.  
     
     
         35 . The method of  claim 32 , further comprising the step of encasing the circuit within an epoxy brick prior to placing the circuit in the housing.  
     
     
         36 . The method of  claim 32 , wherein the pressure is increased to at least about 125 psi.  
     
     
         37 . The method of  claim 32 , wherein the temperature is increased to about 40 degrees centigrade.  
     
     
         38 . The method of  claim 32 , wherein the circuit is inserted into the housing after the optical epoxy is injected into the housing.  
     
     
         39 . The method of  claim 32 , wherein the circuit is inserted into the housing before the optical epoxy is injected into the housing.  
     
     
         40 . A method for fully encasing a circuit within a housing, comprising: 
 inserting the circuit into the glass housing;    injecting an optical epoxy into a glass housing;    injecting an optical epoxy into a second housing;    inserting into the second housing the glass housing containing the circuit;    capping an open end of the glass housing; and    capping an open end of the second housing.    
     
     
         41 . The method of  claim 40 , wherein the second housing comprises PMMA.  
     
     
         42 . The method of  claim 40 , wherein the second housing consists essentially of PMMA.  
     
     
         43 . The method of  claim 40 , further comprising the step of encasing the circuit within an epoxy brick prior to placing the circuit in the glass housing.  
     
     
         44 . The method of  claim 40 , wherein the circuit is inserted into the glass housing after the optical epoxy is injected into the glass housing.  
     
     
         45 . The method of  claim 40 , wherein the circuit is inserted into the glass housing before the optical epoxy is injected into the glass housing.  
     
     
         46 . The method of  claim 40 , wherein the step of capping an open end of the glass housing comprises the step of inserting a glass ball at least partially into said open end of the glass housing.  
     
     
         47 . The method of  claim 40 , further comprising the step of curing the optical epoxy contained in the glass housing prior to inserting the glass housing into the second housing.  
     
     
         48 . The method of  claim 47 , wherein the step of curing the optical epoxy comprises the step of placing the glass housing containing the optical epoxy and the circuit into a pressure vessel and increasing the temperature and pressure within the vessel.  
     
     
         49 . The method of  claim 40 , further comprising the step of curing the optical epoxy contained in the glass housing after inserting the glass housing into the second housing.