Display Panel Touch Photosensing Integration Aperture Ratio

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Solution Overview

Problem

Current display devices face challenges in integrating both touch sensing and photosensing functions efficiently, particularly in maintaining a high aperture ratio and providing various light-based input environments while effectively detecting touch coordinates and light illumination.

Innovation Solution

The display panel incorporates a matrix arrangement of subpixels with phototransistors, photo-driving lines, and photo-control lines, along with a multi-sensing circuit and photo-driving circuit, to enable both touch sensing and photosensing, with electrode and line structures optimized for efficient light-based input detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If both touch sensor configuration and photosensor configuration are integrated in the display panel, then the functionality and user interaction capabilities are enhanced, but the aperture ratio is reduced due to additional electrode and line structures

Engineering Contradiction:
ImprovefunctionalityVSAvoidaperture ratio
Core Design Contradiction:
Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent combines touch sensing and photosensing functions into a single integrated display panel structure. The photosensor configuration shares the same substrate and electrode structures with the touch sensor configuration, merging multiple sensing functions into one unified system rather than using separate independent structures.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The display panel is designed with multi-functional electrode and line structures that serve both touch sensing and photosensing purposes. The same electrode patterns and conductive lines are utilized for multiple sensing modalities, making the structure universal and reducing the need for additional dedicated components.

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

2Measurement precision

If phototransistors, photo-driving lines, and photo-control lines are added to the display panel, then photosensing capability is improved, but the device complexity increases

Engineering Contradiction:
Improvephotosensing capabilityVSAvoidstructure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The photosensing function is segmented into distinct phototransistor units distributed across the display panel, with dedicated photo-driving lines and photo-control lines for each region. This segmentation allows for modular integration and independent optimization of photosensing areas without redesigning the entire display structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent integrates photosensing components in the vertical layering of the display panel structure, placing phototransistors between existing electrode layers. This dimensional integration adds photosensing functionality without significantly increasing the planar footprint or requiring lateral expansion of the device.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Productivity

If electrode and line structures are optimized for photosensing, then photosensing efficiency is improved, but touch sensing performance may be affected

Engineering Contradiction:
Improvephotosensing efficiencyVSAvoidtouch sensing performance
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The electrode and line structures are designed with local quality variations, where specific regions have optimized characteristics for photosensing while other regions maintain properties suitable for touch sensing. The photo-control lines and photo-driving lines are positioned and dimensioned to maximize photosensing efficiency in their respective areas without interfering with touch electrode performance.

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 configuration allows for efficient detection of touch coordinates and light illumination, maintaining a high aperture ratio and supporting various light-based input environments, enhancing the display device's functionality and user interaction capabilities.

Implementation Method 1

a phototransistor, which outputs a photo-control signal in response to illumination light

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP3674859B1Display panel, display device, and driving circuit
Publication Date: 2022.07.13 LG DISPLAY CO LTD
  • EP3674859B1 patent drawingFigure 1
  • EP3674859B1 patent drawingFigure 2
  • EP3674859B1 patent drawingFigure 3

AI summary

A display panel, a display device, and a driving circuit including both a touch sensor configuration and a photosensor configuration are disclosed. The driving circuit comprises a multi-sensing circuit electrically connected to a plurality of common electrodes, disposed in a display panel, through a plurality of read-out lines disposed in the display panel; and a photo-driving circuit driving a plurality of photo-driving lines and a plurality of photo-control lines through which a photo-driving signal and a photo-control signal are transferred to a plurality of phototransistors disposed in the display panel, wherein each of the plurality of phototransistors comprises a gate electrode to which the photo-control signal is applied, a first electrode to which the photo-driving signal is applied, and a second electrode serving as a signal output node, with a signal being output to the second electrode in response to illumination light, and the multi-sensing circuit receives the signal, output from the second electrode of each of the plurality of phototransistors, through a corresponding read-out line among the plurality of read-out lines. A high aperture ratio is obtained since electrode and line structures for touch sensing and photosensing are efficiently designed.