Display Device Lead-Out Line Segmentation for Noise Reduction

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Solution Overview

Problem

In photo sensor type display devices, simultaneous sensing and display timing leads to noise issues due to parasitic capacitance, which increases with larger screen sizes and resolutions, affecting the aperture ratio and transmittance.

Innovation Solution

The implementation of first and second photo touch sensors on both sides of a lead-out line, with sensing data and gate lines configured to transmit charges during one sensing timing, reduces noise and maintains aperture ratio by minimizing parasitic capacitance through a DRD structure and reduced lead-out lines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If sensing and display timing are performed simultaneously in a photo sensor type display device, then the device can operate with simultaneous sensing and display functions, but noise occurs due to the ripple of common voltage transmitted through the lead-out line caused by data signal transitions

Engineering Contradiction:

Improvesimultaneous sensing and display operationVSAvoidnoise due to common voltage ripple

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the lead-out line into multiple sections by introducing intermediate connection points to data lines. This segmentation divides the long lead-out line into shorter segments, reducing the parasitic capacitance of each segment and thereby minimizing the noise caused by common voltage ripple during simultaneous sensing and display operations.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces intermediate connection points as mediators between the lead-out line and data lines. These intermediate points act as buffering zones that isolate the sensing circuit from the voltage ripple generated by data signal transitions, reducing noise transmission while maintaining simultaneous operation capability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Area of stationary object

If the screen size and resolution are increased, then the display quality and viewing area are improved, but the parasitic capacitance of the lead-out line increases sharply, causing increased noise in sensing

Engineering Contradiction:

Improvescreen size and resolutionVSAvoidparasitic capacitance and noise

Core Design Contradiction:

Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

By segmenting the lead-out line into multiple shorter sections connected to intermediate data lines, the patent reduces the length of each individual lead-out segment. This segmentation directly reduces the parasitic capacitance of each segment, allowing for increased screen size and resolution without proportionally increasing noise levels.

Inventive Principle:

Principle #1Segmentation

3Measurement precision

If the charge amount of the sensor is increased to maximize the difference between sensing value and noise, then the sensing signal strength is improved, but the sensor storage capacitor affects the aperture ratio of the display panel

Engineering Contradiction:

Improvesensing signal strengthVSAvoidaperture ratio

Core Design Contradiction:

Measurement precisionVSArea of moving object

Solution Approach 1:

The patent merges the functions of charge storage and signal transmission by utilizing the lead-out line structure itself rather than requiring a separate dedicated storage capacitor. The segmented lead-out line with intermediate connections provides both charge storage capability and reduced parasitic capacitance, improving sensing signal strength without sacrificing aperture ratio.

Inventive Principle:

Principle #5Merging (Combining)

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 enhances charging characteristics, reduces noise, and maintains high aperture ratio and transmittance, allowing for increased screen size and resolution while minimizing the number of lead-out lines by 50%.

Implementation Method 1

a photo touch sensor that recognizes a touch according to light intensity and a capacitance touch sensor that recognizes a touch according to a capacitance variation

Methodology Applied

Scientific EffectPhotoelectric Effect: Photoelectric Effect

Implementation Method 2

the sensor storage capacitor has a side effect that affects an aperture ratio of the display panel

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS11112911B2Display device

Publication Date: 2021.09.07 LG DISPLAY CO LTD

AI summary

A display device according to an aspect of the present disclosure includes a lead-out line disposed between the data lines in the second direction, first and second photo touch sensors disposed in left and right pixels of the lead-out line and electrically connected to the lead-out line to transmit a touch sensing signal, first and second sensing data lines disposed in the second direction and applying first and second sensor data signals to the first and second photo touch sensors and first and second sensing gate lines disposed in the first direction and applying first and second sensor gate signals to the first and second photo touch sensors.