Transparent Electrode Pad Segmentation for Capacitance Uniformity

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Solution Overview

Problem

Capacitance type input devices experience non-uniform capacitance distributions due to material differences and structural limitations, leading to decreased detection sensitivity and increased manufacturing costs, as well as difficulties in early electrical property inspection of transparent electrode layers.

Innovation Solution

An input device design featuring a light-transmissive substrate with a transparent electrode layer and a wiring layer connected through pad portions at both ends, allowing for uniform capacitance distribution and easy electrical property inspection without damaging the electrode layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If scanning side connection electrodes and detection side connection electrodes are formed at the ends of transparent electrode layers, then connection reliability is improved, but capacitance distribution uniformity deteriorates due to material differences and thickness variations

Engineering Contradiction:

Improveconnection reliabilityVSAvoidcapacitance distribution uniformity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The transparent electrode layer is segmented into multiple regions: a main electrode region for detection and pad portions at both ends for connection. This segmentation allows the pad portions to be optimized for electrical connection while the main region maintains uniform capacitance distribution for accurate touch detection.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the transparent electrode layer are given different functions and properties. The pad portions at the ends are designed with specific geometry and material composition optimized for low-resistance connection, while the central detection region maintains uniform thickness and properties for consistent capacitance distribution across the touch surface.

Inventive Principle:

Principle #3Local quality

2Difficulty of detecting and measuring

If probe pins are caused to directly contact transparent electrode layers for inspection, then electrical property measurement is enabled, but the transparent electrode layer is damaged due to its crack-prone nature

Engineering Contradiction:

Improveelectrical property inspection capabilityVSAvoidelectrode layer integrity

Core Design Contradiction:

Difficulty of detecting and measuringVSReliability

Solution Approach 1:

Pad portions serve as intermediary structures between the transparent electrode layer and external probe pins. These pad portions provide robust mechanical and electrical contact points that can withstand inspection procedures without causing damage to the fragile transparent electrode layer, enabling reliable electrical property measurement while preserving electrode integrity.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If inspection is performed after assembling the input device, then electrode integrity is maintained, but detection sensitivity uniformity deteriorates due to delayed defect detection

Engineering Contradiction:

Improveelectrode integrityVSAvoiddetection sensitivity uniformity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The pad portions are designed to enable preliminary electrical property inspection of the transparent electrode layer before the input device is fully assembled. This allows defects to be detected early in the manufacturing process, enabling corrective actions to be taken before assembly, thereby ensuring detection sensitivity uniformity while maintaining electrode integrity through controlled inspection procedures.

Inventive Principle:

Principle #10Preliminary action

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

The design enhances capacitance uniformity and detection sensitivity, facilitates early defect detection, and reduces manufacturing costs by enabling efficient electrical property measurement through probe pin contact with pad portions.

Implementation Method 1

a transparent electrode layer for detecting change of a capacitance value

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

the transparent electrode layer and the wiring layer are connected to each other through a first pad portion for connection, and a second pad portion for electrical property inspection is electrically connected to another end of the transparent electrode layer

Methodology Applied

Scientific EffectDielectric: Dielectric

Data Source

PatentUS8698025B2Input device

Publication Date: 2014.04.15 ALPS ALPINE CO LTD

AI summary

An input device includes a first transparent substrate, a first transparent electrode layer for detecting change of a capacitance value, and a first drawn wiring layer electrically connected to an end of the first transparent electrode layer. The first transparent electrode layer is formed on an input region of the first transparent substrate, and the first drawn wiring layer is formed on a non-input region surrounding the input region. The first transparent electrode layer and the first drawn wiring layer are connected to each other through a first pad portion for connection, and a second pad portion for electrical property inspection is electrically connected to the other end of the first transparent electrode layer.