# US 2018/0023942 A1 · Flexible Strain Sensors

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- Number: US 2018/0023942 A1
- Document ID: US20180023942A1
- Status: Published application
- Kind: A1
- Application number: 15/672,801
- Filed: 2017-08-09
- Published: 2018-01-25
- Earliest claimed: 2012-10-26
- Assignees: Board of Regents, The University of Texas System
- Applicants: Board of Regents, The University of Texas System
- Inventors: Uday Tata; Smitha Rao; Jung-Chih Chiao
- Web page: https://patentgrep.com/patent/US20180023942A1

## CPC

- G01B 7/16: for measuring the deformation in a solid, e.g. by resistance strain gauge
- A61F 2/1613: {having special lens configurations, e.g. multipart lenses; having particular optical properties, e.g. pseudo-accommodative lenses, lenses having aberration corrections, diffractive lenses, lenses for variably absorbing electromagnetic radiation, lenses having variable focus}
- C23C 14/0605: {Carbon}
- C23C 14/35: by application of a magnetic field, e.g. magnetron sputtering {(C23C14/3457 takes precedence)}
- C23C 14/5813: {using lasers}
- G02C 11/10: {Electronic devices other than hearing aids}
- A61F 2/16: Intraocular lenses
- G02C 7/04: Contact lenses for the eyes (disinfection or sterilisation of contact lenses A61L12/00)
- G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- A61F: FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS (dental prosthetics A61C)
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- G02C: SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES (trial frames for testing the eyes A61B3/04; goggles or eyeshields not having the same features as spectacles A61F9/00)

## Abstract

In one embodiment, a flexible strain sensor includes a flexible polymeric substrate having a top surface and a layer of amorphous carbon formed on the top surface of the substrate.

## Claims

### Claim 1

A flexible strain sensor comprising:
a flexible polymeric substrate having a top surface; and
a layer of amorphous carbon formed on the top surface of the substrate.

### Claim 2 (depends on 1)

The sensor of claim 1, wherein the substrate is a biocompatible polymeric substrate.

### Claim 3 (depends on 1)

The sensor of claim 1, wherein the substrate is a polyimide substrate.

### Claim 4 (depends on 1)

The sensor of claim 1, where in the substrate is approximately 1 μm to 500 μm thick.

### Claim 5 (depends on 1)

The sensor of claim 1, wherein the amorphous carbon layer is approximately 0.01 μm to 100 μm thick.

### Claim 6 (depends on 1)

The sensor of claim 1, wherein the sensor comprises an active region and end members provided at the ends of the active region.

### Claim 7 (depends on 6)

The sensor of claim 6, wherein the active region is an elongated central region.

### Claim 8 (depends on 6)

The sensor of claim 6, wherein the active region is rectangular.

### Claim 9 (depends on 6)

The sensor of claim 6, wherein the active region comprises diagonal segments that together form a chevron shape.

### Claim 10 (depends on 6)

The sensor of claim 6, wherein the active region comprises semicircular loops.

### Claim 11 (depends on 6)

The sensor of claim 6, wherein the active region comprises multiple parallel meandered lines.

### Claim 12 (depends on 11)

The sensor of claim 11, wherein the active region further comprises lateral segments that join the meandered lines.

### Claim 13

A method for fabricating a flexible strain sensor, the method comprising:
depositing piezoresistive amorphous carbon on a surface of a flexible substrate; and
micro-machining the substrate to obtain a desired sensor shape.

### Claim 14 (depends on 13)

The method of claim 13, wherein depositing piezoresistive amorphous carbon comprises sputtering the carbon onto the substrate surface.

### Claim 15 (depends on 14)

The method of claim 14, wherein sputtering the carbon comprises sputtering the carbon onto the substrate surface at a temperature below 200° C.

### Claim 16 (depends on 13)

The method of claim 13, wherein micro-machining comprises laser micro-machining.

### Claim 17

An optical device comprising:
a lens body; and
a flexible strain sensor provided on the lens body, the sensor including a flexible polymeric substrate having a top surface and a layer of amorphous carbon formed on the top surface of the substrate.

### Claim 18 (depends on 17)

The device of claim 17, wherein the optical device is an implantable intraocular lens.

### Claim 19 (depends on 18)

The device of claim 18, wherein the implantable intraocular lens comprises a body and arms that extend from the body and wherein a strain sensor is provided on each arm.

### Claim 20 (depends on 17)

The device of claim 17, wherein the device is a contact lens.