Integrated Touch Screen Pixel Stackup Merging Display and Sensing

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Solution Overview

Problem

Conventional touch screens that integrate touch sensing elements with LCD displays often result in increased weight, thickness, and power consumption, as well as decreased brightness due to the overlay of touch sensor panels on the display.

Innovation Solution

Integrating touch sensing circuitry directly into the display pixel stackup of LCDs, utilizing multi-function circuit elements that operate as both display and touch sensing components, such as capacitors, common electrodes, and conductive wires, to reduce the number of parts and processing steps required, thereby making the display thinner, brighter, and more power-efficient.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a touch sensor panel is overlaid on the display, then touch sensing capability is achieved, but weight and thickness increase

Engineering Contradiction:
Improvetouch sensing capabilityVSAvoiddisplay weight
Core Design Contradiction:
Adaptability or versatilityVSWeight of stationary object

Solution Approach 1:

The patent merges the touch sensor panel with the display structure by integrating touch sensing electrodes and circuitry directly into the display's existing layers, specifically utilizing the common electrode and connection structures already present in the LCD stackup. This consolidation eliminates the need for a separate overlay touch panel, thereby achieving touch sensing capability without increasing display weight.

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If a touch sensor panel is overlaid on the display, then touch sensing capability is achieved, but thickness increases

Engineering Contradiction:
Improvetouch sensing capabilityVSAvoiddisplay thickness
Core Design Contradiction:
Adaptability or versatilityVSLength of stationary object

Solution Approach 1:

The touch sensing functionality is merged into the existing display thickness by utilizing already-present layers such as the common electrode and connection structures. The touch sensing electrodes are formed within the same structural envelope as the display, eliminating the need for additional thickness that would result from overlaying a separate touch panel.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The common electrode and other display structure components are designed to serve dual functions: maintaining display operation and enabling touch sensing. This multi-functionality allows the same physical structures to perform both display and touch sensing roles, thereby achieving touch capability without increasing overall display thickness.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If a touch sensor panel is overlaid on the display, then touch sensing capability is achieved, but power consumption increases

Engineering Contradiction:
Improvetouch sensing capabilityVSAvoidpower consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by stationary object

Solution Approach 1:

The touch sensing circuitry is merged with the display's existing power and signal infrastructure. By utilizing the same connection structures, electrodes, and control circuits for both display and touch functions, the patent eliminates the need for separate power consumption channels, thereby achieving touch sensing capability without proportionally increasing overall power consumption.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The display's common electrode and connection structures are designed to serve multiple functions including display operation and touch sensing. This multi-functionality allows a single set of circuits to handle both display rendering and touch detection, reducing the total power consumption compared to having separate dedicated circuits for each function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Adaptability or versatility

If a touch sensor panel is overlaid on the display, then touch sensing capability is achieved, but display brightness decreases

Engineering Contradiction:
Improvetouch sensing capabilityVSAvoiddisplay brightness
Core Design Contradiction:
Adaptability or versatilityVSIllumination intensity

Solution Approach 1:

The touch sensing electrodes are merged with the display's existing optical structure, specifically utilizing the common electrode and connection structures that are already optimized for light transmission. This integration ensures that the touch sensing elements do not introduce additional optical obstructions, thereby maintaining display brightness while achieving touch sensing capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The touch sensing electrodes are strategically positioned and designed with local optical properties optimized for both touch detection and light transmission. By controlling the material composition, thickness, and pattern of the touch electrodes in specific locations, the patent maintains high brightness in display areas while enabling touch sensing functionality.

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables the creation of thinner, brighter, and more power-efficient touch screens by leveraging existing display components for touch sensing functionality, reducing the need for additional layers and power consumption while maintaining or improving touch sensing capabilities.

Implementation Method 1

Capacitive touch sensor panels can be formed from a matrix of drive and sense lines of a substantially transparent conductive material

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3557390B1Integrated touch screen
Publication Date: 2021.08.11 APPLE INC
  • EP3557390B1 patent drawingFigure 1A~1C
  • EP3557390B1 patent drawingFigure 1D
  • EP3557390B1 patent drawingFigure 1E

AI summary

Displays with touch sensing circuitry integrated into the display pixel stackup are provided. Circuit elements, such as touch signal lines, such as drive lines and sense lines, grounding regions, in the display pixel stackups can be grouped together to form touch sensing circuitry that senses a touch on or near the display. An integrated touch screen can include multi-function circuit elements that can operate as circuitry of the display system to generate an image on the display, and can also form part of a touch sensing system that senses one or more touches on or near the display. The multi-function circuit elements can be, for example, capacitors in display pixels that can be configured to operate as storage capacitors/electrodes, common electrodes, conductive wires/pathways, etc., of the display circuitry in the display system, and that may also be configured to operate as circuit elements of the touch sensing circuitry.