Mesh Touch Panel Electrode with Sub-Pattern Width Ratio

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Solution Overview

Problem

Conventional touch panels face challenges in achieving fine line widths for transparent electrodes due to limitations in printing schemes, leading to reduced permeability and increased process complexity, which affects transmittance and visibility.

Innovation Solution

The touch panel employs a method where the ratio of first to second sub-patterns in width and height is controlled to achieve a fine line width of 3 µm or less, allowing the transparent electrode material to remain only on the first sub-pattern, and using an imprinting process to simplify the formation of sensing and wire electrode patterns with the same electrode material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a printing scheme is used to form a metal mesh pattern, then the manufacturing process is simple, but the minimum line width is limited to about 3 μm to about 5 μm, degrading permeability and visibility

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidline width precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent replaces the conventional printing scheme with a photoresist-based photolithography process. This substitution enables precise control of line width through optical exposure and chemical etching, achieving line widths of about 3 μm or less while maintaining pattern definition and manufacturing feasibility.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If the photoresist scheme is used to form wire electrode and sensing electrode patterns, then the patterns can be formed, but the number of processes increases and process complexity increases, reducing process efficiency

Engineering Contradiction:
Improvepattern formation accuracyVSAvoidnumber of processing steps
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges the formation of wire electrode patterns and sensing electrode patterns into a single photoresist-based photolithography process. By using one photoresist layer and one etching step, both electrode types are formed simultaneously, eliminating the need for separate processing steps and reducing overall process complexity.

Inventive Principle:
Principle #5Merging (Combining)

3Manufacturing precision

If the photoresist scheme is used to form transparent electrode pattern, then the pattern can be formed, but the efficiency in the fabricating process is lowered

Engineering Contradiction:
Improvetransparent electrode pattern accuracyVSAvoidfabricating process efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies preliminary action by forming the photoresist pattern before depositing the transparent electrode material. This sequence allows the photoresist to define the exact pattern geometry in advance, enabling precise material deposition and subsequent etching in a single process flow, thereby improving overall fabrication efficiency.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2738653B1Electrode member and touch panel including the same
Publication Date: 2021.05.19 LG INNOTEK CO LTD
  • EP2738653B1 patent drawingFigure 1
  • EP2738653B1 patent drawingFigure 2~4
  • EP2738653B1 patent drawingFigure 5~7

AI summary

Disclosed is a touch panel. The touch panel includes a substrate (100), and an electrode part (210) formed in a mesh shape on the substrate (100). The electrode part (210) includes a resin layer comprising first and second sub-patterns (310; 320), and a transparent electrode on the first sub-pattern (310). A ratio of a width of the first sub-pattern (310) to a width of the second sub-pattern (320) is in a range of 1:0.01 to 1:0.5.