In-Cell Touch Electrode Layout for White Balance and Aperture Ratio

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Solution Overview

Problem

The existing liquid crystal display devices with in-cell touch panels face challenges in maximizing transmissivity and display quality due to differences in footprint between blue and other pixel electrodes, leading to adjustments in white balance and parasitic capacitances that affect display quality.

Innovation Solution

The configuration includes pixel electrodes, signal lines, a common electrode, and position detection electrodes, where the position detection lines are disposed between the signal lines and pixel electrodes to create potential differences, allowing for equalized areas and reduced parasitic capacitance, thereby enhancing the aperture ratio and minimizing display failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the footprint of blue pixel electrodes is made smaller to accommodate touch panel structure, then the touch panel function is achieved, but white balance adjustment becomes difficult and display quality decreases

Engineering Contradiction:

Improvetouch panel functionVSAvoidwhite balance adjustment

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The common electrode is divided into multiple position detection electrodes that are selectively connected to signal lines. This segmentation allows different regions to have different functions: some areas maintain full common electrode coverage for display, while others have position detection electrodes for touch input, resolving the conflict between touch functionality and display quality

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The common electrode serves dual purposes: it functions as both the common electrode for LCD operation and as position detection electrodes for touch panel functionality. By dividing and selectively connecting portions of the common electrode, the system achieves multi-functionality without compromising white balance or requiring separate electrode structures

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Difficulty of detecting and measuring

If position detection lines are disposed adjacent to pixel electrodes, then position detection is achieved, but parasitic capacitance increases and display quality decreases

Engineering Contradiction:

Improveposition detectionVSAvoidparasitic capacitance

Core Design Contradiction:

Difficulty of detecting and measuringVSObject-generated harmful factors

Solution Approach 1:

An insulating film is introduced as an intermediary between the position detection lines and the common electrode. This intermediate layer reduces the parasitic capacitance between these conductive elements while still allowing the position detection function to operate, thereby eliminating the harmful electrical interaction

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The position detection lines are disposed between signal lines and pixel electrodes rather than directly adjacent to pixel electrodes. This spatial rearrangement in another dimension reduces the capacitive coupling and parasitic effects while maintaining detection capability

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Manufacturing precision

If the interval between signal lines is reduced to increase pixel density, then display resolution is improved, but aperture ratio decreases and transmissivity is reduced

Engineering Contradiction:

Improvepixel densityVSAvoidaperture ratio

Core Design Contradiction:

Manufacturing precisionVSArea of stationary object

Solution Approach 1:

The common electrode and position detection electrodes are merged into a single structural element. By dividing the common electrode and selectively connecting portions to signal lines, the patent eliminates the need for separate position detection electrode structures, thereby increasing the aperture ratio and light transmissivity while maintaining high pixel density

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 configuration improves the display quality by allowing for easier adjustment of white balance and maximizing display intensity while reducing parasitic capacitance differences, leading to a more stable and efficient position input function.

Implementation Method 1

configured so that a position input member for position input operation and the at least one position detection electrode form a capacitor to detect a position of input by the position input member

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS10747041B2Display device with position input function

Publication Date: 2020.08.18 SHARP KK

AI summary

A display device with a position input function includes pixel electrodes, signal lines, a common electrode, a position detection electrode, and position detection lines. The signal lines are disposed adjacent to the pixel electrodes. The common electrode is disposed to overlap the pixel electrodes via an insulating film. The position detection lines are connected to the one position detection electrode via a contact hole formed in the insulating film that is disposed between the common electrode and the position detection lines. Each of the position detection lines is disposed between the signal line and the pixel electrode such that two of the position detection lines sandwich the pixel electrodes and the signal lines. An interval between two of the signal lines that sandwich the pixel electrodes and the position detection lines is larger than an interval between two of the signal lines that sandwich the pixel electrodes.