# US 2014/0192277 A1 · Low-birefringence substrate for touch sensor

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- Number: US 2014/0192277 A1
- Document ID: US20140192277A1
- Status: Published application
- Kind: A1
- Application number: 14/204,949
- Filed: 2014-03-11
- Published: 2014-07-10
- Earliest claimed: 2011-11-22
- Assignees: Atmel Corporation
- Inventors: Esat Yilmaz; Neerja Saran; David Brent Guard
- Web page: https://patentgrep.com/patent/US20140192277A1

## CPC

- G06F 3/0445: {using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer}
- G02B 1/04: made of organic materials, e.g. plastics (G02B1/08 takes precedence)
- G02B 1/10: Optical coatings produced by application to, or surface treatment of, optical elements (G02B1/08 takes precedence)
- G02F 1/13338: {Input devices, e.g. touch panels}
- G06F 3/0412: {Digitisers structurally integrated in a display}
- G06F 3/0443: {using a single layer of sensing electrodes}
- G06F 3/0446: {using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes}
- H10K 59/40: OLEDs integrated with touch screens
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES

## Abstract

In one embodiment, an apparatus includes a substrate including material having a low birefringence. One or more electrodes of a touch sensor are disposed on the substrate.

## Claims

### Claim 1

An apparatus comprising:
a substrate comprising material having a low birefringence; and
one or more electrodes of a touch sensor disposed on the substrate.

### Claim 2 (depends on 1)

The apparatus of claim 1, wherein the substrate is located above a display.

### Claim 3 (depends on 1)

The apparatus of claim 1, wherein the material having a low birefringence is cyclic olefin polymer, cyclic olefin copolymer, cyclic block copolymer, tri-acetate cellulose, or polyethersulfone.

### Claim 4 (depends on 1)

The apparatus of claim 1, wherein the substrate has a substantially uniform thickness that is between approximately 10 micrometers and approximately 200 micrometers.

### Claim 5 (depends on 1)

The apparatus of claim 1, wherein the material having a low birefringence has a maximum difference between refractive indices of less than approximately 1.5×10−4.

### Claim 6 (depends on 1)

The apparatus of claim 1, wherein the substrate has a single-pass optical retardation of less than approximately 30 nanometers.

### Claim 7 (depends on 1)

The apparatus of claim 1, wherein the electrodes are made of a conductive mesh of conductive material.

### Claim 8 (depends on 1)

The apparatus of claim 1, wherein the substrate is located below a polarization layer.

### Claim 9 (depends on 8)

The apparatus of claim 8, wherein the polarization layer comprises a linear polarizer or a combination of the linear polarizer and a quarter-wave plate.

### Claim 10 (depends on 1)

The apparatus of claim 1, wherein:
one or more first ones of the electrodes are disposed on a first surface of the substrate; and
one or more second ones of the electrodes are disposed on a second surface of the substrate.

### Claim 11 (depends on 1)

The apparatus of claim 1, wherein all the electrodes are disposed on a single surface of the substrate.

### Claim 12 (depends on 1)

The apparatus of claim 1, wherein:
the apparatus comprises two substrates comprising material having low birefringence;
one or more of the electrodes are disposed on a surface of a first one of the substrates; and
one or more of the electrodes are disposed on a surface of a second one of the substrates.

### Claim 13

A device comprising:
a substrate comprising material having a low birefringence;
one or more electrodes of a touch sensor disposed on the substrate; and
one or more computer-readable non-transitory storage media embodying logic that is configured when executed to control the touch sensor.

### Claim 14 (depends on 13)

The device of claim 13, further comprising a display located below the substrate.

### Claim 15 (depends on 13)

The device of claim 13, wherein the material having a low birefringence is cyclic olefin polymer, cyclic olefin copolymer, cyclic block copolymer, tri-acetate cellulose, or polyethersulfone.

### Claim 16 (depends on 13)

The device of claim 13, wherein the substrate has a substantially uniform thickness that is between approximately 10 micrometers and approximately 200 micrometers.

### Claim 17 (depends on 13)

The device of claim 13, wherein the material having a low birefringence has a maximum difference between refractive indices of less than approximately 1.5×10−4.

### Claim 18 (depends on 13)

The device of claim 13, wherein the substrate has a single-pass optical retardation of less than approximately 30 nanometers.

### Claim 19 (depends on 13)

The device of claim 13, wherein the substrate is located below a polarization layer.

### Claim 20 (depends on 19)

The device of claim 19, wherein the polarization layer comprises a linear polarizer or a combination of the linear polarizer and a quarter-wave plate.