Ultra-Thin Touch Sensor Stack-Up With Integrated Polarizer

Solution Overview

Problem

Conventional touch screens have a thick stack-up structure due to the inclusion of flex circuits and separate substrates for touch sensor panels and polarizers, which increases device thickness, weight, and reduces optical image quality by increasing the display-to-cover glass distance.

Innovation Solution

The implementation of an ultra-thin touch screen stack-up design that eliminates flex circuits and integrates the touch sensor panel with the polarizer using a flexible substrate, allowing for routing of touch electrodes and shield layers to reduce thickness and weight, and improves optical image quality by minimizing the display-to-cover glass distance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If flex circuits and separate substrates are used for touch sensor panels and polarizers, then the touch screen can be assembled with standard components, but the device thickness and weight increase

Engineering Contradiction:

Improveassembly with standard componentsVSAvoiddevice thickness

Core Design Contradiction:

Ease of manufactureVSLength of moving object

Solution Approach 1:

The patent combines the touch sensor panel and polarizer onto a single flexible substrate, eliminating the need for separate substrates and flex circuits. This merging of components directly reduces device thickness while maintaining manufacturability through integrated assembly processes.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The flexible substrate serves multiple functions simultaneously: it acts as the base for the touch sensor panel, supports the polarizer, and provides the structural framework. This multi-functionality eliminates the need for dedicated flex circuits and separate mounting structures, reducing overall thickness.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Ease of manufacture

If flex circuits and separate substrates are used for touch sensor panels and polarizers, then the touch screen can be assembled with standard components, but the device weight increases

Engineering Contradiction:

Improveassembly with standard componentsVSAvoiddevice weight

Core Design Contradiction:

Ease of manufactureVSWeight of moving object

Solution Approach 1:

The patent combines the touch sensor panel and polarizer onto a single flexible substrate, eliminating the need for separate substrates and flex circuits. This merging of components directly reduces device thickness while maintaining manufacturability through integrated assembly processes.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The flexible substrate serves multiple functions simultaneously: it acts as the base for the touch sensor panel, supports the polarizer, and provides the structural framework. This multi-functionality eliminates the need for dedicated flex circuits and separate mounting structures, reducing overall thickness.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of manufacture

If the display-to-cover glass distance is increased due to thick stack-up, then assembly is easier, but optical image quality deteriorates

Engineering Contradiction:

Improveassembly easeVSAvoidoptical image quality

Core Design Contradiction:

Ease of manufactureVSIllumination intensity

Solution Approach 1:

The patent combines the touch sensor panel and polarizer onto a single flexible substrate, eliminating the need for separate substrates and flex circuits. This merging of components directly reduces device thickness while maintaining manufacturability through integrated assembly processes.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The use of a flexible substrate allows for a thin-film construction that minimizes the distance between the display and cover glass. This thin-film approach maintains ease of assembly while significantly improving optical image quality by reducing light scattering and distortion.

Inventive Principle:

Principle #30Flexible shells and thin films

Data Source

PatentUS11853515B2Ultra-thin touch sensors

Publication Date: 2023.12.26 APPLE INC

AI summary

Touch screens with ultra-thin stack-ups can provide for a lower profile device, can improve the optical image on the display by reducing the display to cover glass distance, and can reduce the weight of the device. In some examples, the thickness of the touch screen stack-up can be reduced and/or the border region reduced, by removing the flex circuit connection from the stack-up. A flexible substrate can be used to enable routing of touch electrodes to touch circuitry. In some examples including a shield layer, the thickness of the touch screen stack-up can be reduced by routing the shield layer to a shield electrode on the touch sensor panel. The shield layer can then be routed to touch sensing circuitry via the flexible substrate. In some examples, the touch sensor panel or a portion of thereof can be integrated with the polarizer.