Methods and apparatus for forming a polymer layer around a structure using a plurality of protrusions

1. A method comprising:

positioning a structure on a plurality of protrusions that extend from a surface of a molding piece, wherein the structure comprises a sensor or an electronic component;

forming, using the molding piece, a body-mountable device by forming a polymer layer around the structure positioned on the plurality of protrusions, such that the structure is at least partially enclosed by the polymer layer, wherein the polymer layer defines a first side of the body-mountable device and a second side of the body-mountable device opposite the first side, wherein the surface of the molding piece supports the polymer layer as the polymer layer is being formed, and wherein forming the polymer layer comprises:

providing a polymer material on the surface of the molding piece,

bringing the molding piece and a press together into a forming position, wherein the press comprises a second plurality of protrusions that extend from a surface of the press, and wherein in the forming position the molding piece and press apply pressure to the polymer material, and

in the forming position, (i) conforming, using the second plurality of protrusions, the structure to a curvature of the polymer layer and (ii) curing the polymer material to form the polymer layer, wherein curing the polymer material comprises:

after providing the polymer material, curing the polymer material to a uniform partially-cured state, such that the partially-cured polymer material supports the structure as the polymer layer is being formed, wherein curing the polymer material to the uniform partially-cured state comprises curing the polymer material to the uniform partially-cured state using light,

after curing the polymer material to the uniform partially-cured state, retracting the plurality of protrusions through the surface of the molding piece, and

after retracting the plurality of protrusions, curing the polymer material to a fully-cured state to form the polymer layer, wherein curing the polymer material to the fully-cured state comprises curing the polymer material to the fully-cured state using light; and

removing the body-mountable device from the molding piece.

2. The method of claim 1 , wherein the body-mountable device removed from the molding piece has a plurality of indentations in the polymer layer formed by the retraction of the plurality of protrusions.

3. The method of claim 1 , wherein the plurality of protrusions comprises at least three protrusions.

4. The method of claim 1 , wherein each protrusion of the plurality of protrusions has a diameter between 50 micrometers to 2 millimeters.

5. The method of claim 1 , wherein each protrusion of the plurality of protrusions comprises one or more of a metal, a non-stick material, or a plastic.

6. The method of claim 1 , wherein the structure has a plurality of alignment features, and wherein positioning the structure on the plurality of protrusions comprises aligning the plurality of alignment features with the plurality of protrusions.

7. The method of claim 1 , wherein the surface of the molding piece is substantially symmetric about an axis, and wherein each protrusion of the plurality of the protrusions extends from the surface in a respective direction that is substantially parallel to the axis.

8. The method of claim 1 , wherein the surface of the molding piece is substantially symmetric about an axis, and wherein at least one protrusion of the plurality of the protrusions extends from the surface in a respective direction that is non-parallel to the axis.

9. The method of claim 1 , further comprising applying a non-stick coating to at least one protrusion of the plurality of protrusions.

10. The method of claim 1 , wherein forming the polymer layer further comprises:

retracting the second plurality of protrusions through the surface of the press.

11. The method of claim 1 , wherein the structure comprises the sensor, wherein the molding piece further comprises a third protrusion that extends from the surface to the sensor through the polymer layer as the polymer layer is being formed, and wherein the body-mountable device removed from the molding piece has a channel to the sensor formed by the third protrusion.

12. The method of claim 1 , wherein the structure comprises the sensor, and wherein the method further comprises:

forming a protective layer over the sensor, such that the sensor is enclosed by the protective layer; and

removing the protective layer to form a channel to the sensor through the polymer layer,

wherein forming the polymer layer around the structure comprises forming the polymer layer around the structure, such that the structure is enclosed by the polymer layer and the protective layer.

13. A method comprising:

positioning a structure on a plurality of protrusions that extend from a surface of a molding piece, wherein the structure comprises a sensor or an electronic component;

forming, using the molding piece, a body-mountable device by forming a polymer layer around the structure positioned on the plurality of protrusions, such that the structure is at least partially enclosed by the polymer layer, wherein the polymer layer defines a first side of the body-mountable device and a second side of the body-mountable device opposite the first side, wherein the surface of the molding piece supports the polymer layer as the polymer layer is being formed, and wherein forming the polymer layer comprises:

providing a polymer material on the surface of the molding piece,

after providing the polymer material, conforming, using a second plurality of protrusions opposite the plurality of protrusions, the structure to a curvature of the polymer layer,

after providing the polymer material, curing the polymer material to a uniform partially-cured state, such that the partially-cured polymer material supports the structure as the polymer layer is being formed, wherein curing the polymer material to the uniform partially-cured state comprises curing the polymer material to the uniform partially-cured state using light,

after curing the polymer material to the uniform partially-cured state, retracting the plurality of protrusions through the surface of the molding piece, and

after retracting the plurality of protrusions, curing the polymer material to a fully-cured state to form the polymer layer, wherein curing the polymer material to the fully-cured state comprises curing the polymer material to the fully-cured state using light; and

removing the body-mountable device from the molding piece.