Transparent Touch Display Routing Layout for Reliable Detection

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Solution Overview

Problem

Transparent touch display apparatuses face issues with reduced transmittance and distorted touch signals due to the increased number and density of routing lines outside the emission and transmission areas.

Innovation Solution

The solution involves disposing touch electrodes with higher transmittance than routing lines on the transmission area, using transparent conductive materials like ITO and IZO, and routing lines made of metal with lower resistance, positioned outside the emission and transmission areas, along with a black matrix to prevent moire phenomena and minimize transmittance loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the number of routing lines is increased to improve touch detection precision, then the transmittance of the transparent display apparatus decreases

Engineering Contradiction:
Improvetouch detection precisionVSAvoidtransmittance
Core Design Contradiction:
Measurement precisionVSIllumination intensity

Solution Approach 1:

The routing lines are segmented into multiple layers (first routing line layer and second routing line layer) stacked on the encapsulating element. This segmentation allows the routing lines to be distributed in three-dimensional space, reducing their projected density on the transmission area while maintaining sufficient routing capacity for precise touch detection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The routing lines are extended from a two-dimensional plane to a three-dimensional structure by stacking multiple layers. The first routing line layer and second routing line layer are positioned at different heights, utilizing the vertical dimension to reduce the visual and functional density of routing lines on the transmission area, thereby maintaining high transmittance while supporting sufficient routing capacity for precise touch detection.

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

2Measurement precision

If the density of routing lines is increased to improve touch detection precision, then distortion of touch signal occurs

Engineering Contradiction:
Improvetouch detection precisionVSAvoidtouch signal reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The routing lines are divided into multiple separate layers (first routing line layer and second routing line layer) rather than being concentrated in a single dense layer. This segmentation reduces the density of routing lines in any single plane, minimizing their collective impact on touch signal integrity while maintaining the overall routing capacity needed for precise touch detection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

By distributing routing lines across multiple vertical layers, the patent reduces the planar density of routing lines that could interfere with touch signals. The vertical separation between the first routing line layer and second routing line layer creates spatial isolation that reduces signal distortion while maintaining sufficient routing capacity.

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

3Device complexity

If routing lines are disposed on the transmission area to simplify structure, then the transmittance of the transparent display apparatus decreases

Engineering Contradiction:
Improvestructure complexityVSAvoidtransmittance
Core Design Contradiction:
Device complexityVSIllumination intensity

Solution Approach 1:

The routing lines are extracted from the transmission area and repositioned to be disposed outside both the emission area and transmission area. This extraction removes the harmful element (routing lines) from the region where it causes transmittance degradation, while the routing lines remain functional for connecting touch electrodes.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The routing lines are positioned in a different spatial zone - outside the emission and transmission areas - rather than being layered over the transmission area. This spatial repositioning maintains structural functionality while preserving the optical properties of the transmission area.

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

Data Source

PatentEP4024470B1Transparent touch display apparatus
Publication Date: 2026.03.25 LG DISPLAY CO LTD
  • EP4024470B1 patent drawingFigure 1
  • EP4024470B1 patent drawingFigure 2
  • EP4024470B1 patent drawingFigure 3~4

AI summary

A transparent touch display apparatus including a device substrate (100), a touch electrode (TE) and a routing line (700). The device substrate (100) may include an emission area (EA) and a transmission area (TA). The touch electrode (TE) may be disposed on the transmission area (TA) of the device substrate (100). The routing line (700) may be disposed outside the emission area (EA) and the transmission area (TA) of the device substrate (100). A transmittance of the touch electrode (TE) may be higher than a transmittance of the routing line (700). Thus, in the transparent touch display apparatus, the reliability of the touch detection may be improved.