Encapsulated Electronics In An Eye-Mountable Device

• US 20140200424A1
• Filed: 01/15/2013
• Published: 07/17/2014
• Est. Priority Date: 01/15/2013
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Etzkorn, James, Amirparviz, Babak
• Granted Patent: US 8,874,182 B2
• Time in Patent Office: Days
• US Class Current: 600/345
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/0004 characterised by the type of physiological signal transmitted
• CPC Class Codes: A61B 5/14507 specially adapted for measuring characteristics of body fluids other than blood devices for taking samples of body liquids A61B10/0045
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/1468 using chemical or electrochemical methods, e.g. by polarographic means A61B5/1486 takes precedence
• CPC Class Codes: A61B 5/1473 invasive, e.g. introduced into the body by a catheter A61B5/1482 takes precedence
• CPC Class Codes: A61B 5/1486 using enzyme electrodes, e.g. with immobilised oxidase
• CPC Class Codes: A61B 5/14865 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors
• CPC Class Codes: A61B 5/6821 Eye
• CPC Class Codes: A61B 5/6867 specially adapted to be attached or implanted in a specific body part A61B5/6847 takes precedence
• CPC Class Codes: B29D 11/00038 Production of contact lenses
• CPC Class Codes: B29D 11/00817 Producing electro-active lenses or lenses with energy receptors, e.g. batteries or antennas
• CPC Class Codes: G01N 27/3271 Amperometric enzyme electrodes for analytes in body fluids, e.g. glucose in blood amperometry per se G01N27/49; aspects concerning the enzyme reagent C12Q1/001
• CPC Class Codes: G02C 7/04 Contact lenses for the eyes disinfection or sterilisation of contact lenses A61L12/00
• CPC Class Codes: H01L 21/568 Temporary substrate used as encapsulation process aid H01L21/4832 and H01L21/566 take precedence
• CPC Class Codes: H01L 2224/81001 involving a temporary auxiliary member not forming part of the bonding apparatus
• CPC Class Codes: H01L 23/3107 the device being completely enclosed
• CPC Class Codes: H01Q 1/273 Adaptation for carrying or wearing by persons or animals
• CPC Class Codes: H02J 2310/23 The load being a medical device, a medical implant, or a life supporting device
• CPC Class Codes: H02J 50/005 : Mechanical details of housing or structure aiming to accommodate the power transfer means, e.g. mechanical integration of coils, antennas or transducers into emitting or receiving devices
• CPC Class Codes: H02J 50/20 : using microwaves or radio frequency waves
• CPC Class Codes: H04B 5/20 : characterised by the transmission technique; characterised by the transmission medium
• CPC Class Codes: H04B 5/45 : Transponders
• CPC Class Codes: H04B 5/72 : for local intradevice communication
• CPC Class Codes: H04B 5/79 : for data transfer in combination with power transfer
• CPC Class Codes: Y10T 29/49826 : Assembling or joining

Abstract

An eye-mountable device includes an electrochemical sensor embedded in a polymeric material configured for mounting to a surface of an eye. The electrochemical sensor includes a working electrode and a reference electrode that reacts with an analyte to generate a sensor measurement related to a concentration of the analyte in a fluid to which the eye-mountable device is exposed. An example assembly process includes: forming a sacrificial layer on a working substrate; forming a first layer of a bio-compatible material on the sacrificial layer; providing an electronics module on the first layer of the bio-compatible material, forming a second layer of the bio-compatible material to cover the electronics module; and annealing the first and second layers of the bio-compatible material together to form an encapsulated structure having the electronics module fully encapsulated by the bio-compatible material.

Claims

1. An eye-mountable device comprising:

a transparent polymeric material having a concave surface and a convex surface, wherein the concave surface is configured to be removably mounted over a corneal surface and the convex surface is configured to be compatible with eyelid motion when the concave surface is so mounted; and

a substrate at least partially embedded in the transparent polymeric material, wherein the substrate comprises a first layer of a bio-compatible material, a second layer of the bio-compatible material, an electrochemical sensor that includes a working electrode and a reference electrode and an electronics module, wherein portions of the first and second layers of the bio-compatible material are annealed together such that the electronics module is encapsulated within the bio-compatible material, wherein the second layer has an opening that exposes the working electrode and reference electrode, and wherein the electronics module includes;

an antenna; and

a controller electrically connected to the electrochemical sensor and the antenna, wherein the controller is configured to control the electrochemical sensor to obtain a sensor measurement related to a concentration of an analyte in a fluid to which the eye-mountable device is exposed and use the antenna to indicate the sensor measurement.

3. The eye-mountable device according to claim 1, wherein the substrate has a thickness of less than 150 micrometers.

4. The eye-mountable device according to claim 1, wherein the substrate is ring-shaped and is embedded near the periphery of the transparent polymeric material in the eye-mountable device so as not to interfere with light transmission through the central portion of the eye-mountable device.

5. The eye-mountable device according to claim 1, wherein the electronics module includes an energy harvesting system that captures electrical energy from incident radiation to power the electronics module.

6. The eye-mountable device according to claim 1, wherein the bio-compatible material includes a dichlorodi-p-xylylene polymer.

2. (canceled)

7. A method comprising:

forming a first layer of a bio-compatible material;

providing an electronics module on the first layer of the bio-compatible material;

forming a working electrode and a reference electrode of an electrochemical sensor on the first layer of the bio-compatible material;

forming a second layer of the bio-compatible material to cover the electronics module, the working electrode, and the reference electrode; and

annealing portions of the first and second layers of the bio-compatible material together to form an encapsulated structure, wherein the encapsulated structure comprises the electronics module fully enclosed within the bio-compatible material; and

after the annealing, forming an opening in the second layer of the bio-compatible material to expose the working electrode and reference electrode.

8. The method according to claim 7, further comprising:

forming a sacrificial layer on a working substrate, wherein the first layer of the bio-compatible material is formed on the sacrificial layer;

removing the sacrificial layer to release the encapsulated structure from the working substrate.

9. The method according to claim 8, wherein the first and second layers of the bio-compatible material and the electronics module have a combined thickness of less than 150 micrometers.

10. The method according to claim 7, wherein the first layer of the bio-compatible material, the electronics module, and the second layer of the bio-compatible material are all stacked over a sacrificial layer on a working substrate during the annealing, and wherein the annealing includes baking the working substrate in an oven.

11. The method according to claim 7, further comprising:

etching the encapsulated structure to form a ring-shaped structure that comprises the electronics module encapsulated in the bio-compatible material.

12. The method according to claim 11, further comprising:

embedding the ring-shaped structure in an eye-mountable device including a transparent polymeric material having a concave surface and a convex surface, wherein the concave surface is configured to be removable mounted over a corneal surface, and wherein the convex surface is configured to be compatible with eyelid motion when the concave surface is so mounted.

13. The method according to claim 7, wherein the bio-compatible material includes a dichlorodi-p-xylylene polymer.

14. The method according to claim 7, further comprising forming a sacrificial layer including a photoresist or a non-stick material on a working substrate so as to separate the bio-compatible material from the working substrate during the annealing.

15. The method according to claim 7, wherein providing the electronics module comprises:

patterning metal to form;

connection pads configured to receive a chip, an antenna, antenna interconnects between at least one of the connections pads and one or more of the antenna leads, and sensor interconnects between at least one of the connection pads and one or more of the electrodes of the electrochemical sensor; and

applying a chip to the connection pads, wherein the chip is configured to control the electrochemical sensor to obtain a sensor measurement related to a concentration of the analyte in a fluid to which the electrochemical sensor is exposed and use the antenna to wirelessly indicate the sensor measurement.

16. The method according to claim 15, wherein the applying the chip to the connection pads includes electrically connecting the chip to the connection pads via an anisotropic conductive adhesive.

17. The method according to claim 7, wherein the electronics module includes an energy harvesting system that captures electrical energy from incident radiation to power the electronic components while encapsulated in the bio-compatible material.

18. A device prepared by a process comprising:

forming a first layer of a bio-compatible material;

providing an electronics module on the first layer of the bio-compatible material;

forming a working electrode and a reference electrode of an electrochemical sensor on the first layer of the bio-compatible material;

forming a second layer of the bio-compatible material to cover the electronics module, the working electrode, and the reference electrode; and

annealing portions of the first and second layers of the bio-compatible material together to form an encapsulated structure, wherein the encapsulated structure comprises the electronics module fully enclosed within the bio-compatible material; and

after the annealing, forming an opening in the second layer of the bio-compatible material to expose the working electrode and reference electrode.

19. The device according to claim 18, wherein the process further comprises:

forming a sacrificial layer on a working substrate, wherein the first layer of the bio-compatible material is formed on the sacrificial layer;

removing the sacrificial layer to release the encapsulated structure from the working substrate.

20. The device according to claim 18, wherein the process further comprises:

etching the encapsulated structure to form a ring-shaped structure that comprises the electronics module encapsulated in the bio-compatible material; and

embedding the ring-shaped structure in an eye-mountable device including a transparent polymeric material having a concave surface and a convex surface, wherein the concave surface is configured to be removable mounted over a corneal surface, and wherein the convex surface is configured to be compatible with eyelid motion when the concave surface is so mounted.