Touch Sensor Insulating Layer for Capacitance Uniformity

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Solution Overview

Problem

Existing touch sensors face challenges in maintaining consistent touch sensitivity due to variations in mutual capacitance caused by differences in the area and connection structure of unit areas in the sensing area.

Innovation Solution

The implementation of an insulating layer exclusively in a subset of unit areas of the touch sensor, where sensor electrodes are located, helps to compensate for variations in mutual capacitance by adjusting the thickness and area coverage of the insulating layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If an insulating layer is disposed on all unit areas, then manufacturing simplicity is maintained, but variations in mutual capacitance increase due to differences in unit area connection structures

Engineering Contradiction:

Improvemutual capacitance consistencyVSAvoidinsulating layer configuration

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The insulating layer is selectively disposed only on sensor electrodes in specific unit areas (first unit areas) rather than uniformly across all unit areas. This local differentiation compensates for capacitance variations by providing insulation where needed while leaving other areas unchanged, thereby resolving the contradiction between manufacturing simplicity and capacitance consistency.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The insulating layer modifies the electrical parameters (capacitance) of sensor electrodes in specific unit areas by changing the dielectric environment. This parameter adjustment compensates for variations caused by different connection structures, achieving more uniform mutual capacitance across the sensing area.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the insulating layer is disposed on sensor electrodes in all unit areas, then touch sensitivity uniformity improves, but manufacturing complexity increases

Engineering Contradiction:

Improvetouch sensitivity consistencyVSAvoidinsulating layer fabrication

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The insulating layer is selectively applied only to sensor electrodes in first unit areas where it is most needed for sensitivity uniformity, rather than being uniformly applied to all unit areas. This selective approach maintains touch sensitivity consistency while reducing fabrication complexity compared to a full-coverage insulating layer.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If unit areas have different connection structures, then sensor electrode arrangement flexibility increases, but mutual capacitance variations increase

Engineering Contradiction:

Improvesensor electrode arrangementVSAvoidmutual capacitance uniformity

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The insulating layer is selectively disposed on sensor electrodes in specific unit areas to compensate for capacitance variations introduced by different connection structures. This local compensation allows the sensor to maintain capacitance uniformity while preserving the flexibility of having different connection structures in different areas.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20250060853A1Touch sensor including an insulating layer and display device including the same

Publication Date: 2025.02.20 SAMSUNG DISPLAY CO LTD

AI summary

A display device according to an embodiment includes a display layer including pixels located in a display area, a sensor layer including a sensing area overlapping with the display area and unit areas corresponding to touch nodes located in the sensing area, sensor electrodes disposed in the unit areas of the sensor layer, sensor lines electrically connected to the sensor electrodes, and an insulating layer provided exclusively in a subset of the unit areas and disposed on portions of the sensor electrodes.