Touch Sensor Intermediate Layer Design for Display Fabrication Reliability
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Solution Overview
Problem
Existing display devices with touch sensors face reliability issues during the fabrication process, particularly in the integration of touch sensors with display elements, leading to defects and performance inconsistencies.
Innovation Solution
A display device design that includes a substrate with a display region and a non-display region, featuring a touch sensor structure with a base layer, conductive patterns, insulating layers, an intermediate organic layer, and a conductive cover layer, where the intermediate layer fills openings in the non-display region and is protected by the cover layer to enhance reliability and prevent defects during fabrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If touch sensors are integrated with display elements in existing display devices, then touch sensing functionality is achieved, but reliability issues and defects occur during fabrication
Solution Approach 1:
The touch sensor structure is divided into multiple distinct layers including base layer, first conductive pattern layer, first insulating layer, second conductive pattern layer, second insulating layer, intermediate layer, and cover layer. This segmentation allows each layer to be fabricated and optimized independently, reducing defects while maintaining integration functionality.
Solution Approach 2:
An intermediate layer is introduced between the base layer and the cover layer to serve as a mediator. This intermediate layer includes openings that expose pads in the non-display region, enabling proper electrical connections while protecting the underlying structures during fabrication processes.
2Ease of operation
If multiple layers including conductive patterns and insulating layers are stacked to form touch sensor, then touch sensing functionality is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The base layer is formed first with predetermined patterns, followed by sequential formation of conductive patterns and insulating layers. The intermediate layer is formed with openings that align with pads before the cover layer is applied, ensuring proper electrical connections are established in advance of final assembly.
Solution Approach 2:
The patent employs a multi-layer structure where the intermediate layer acts as a temporary protective and connective structure during fabrication. This intermediate layer facilitates precise alignment and connection establishment, then serves its purpose during testing and operation.
3Measurement precision
If pads are exposed in non-display region for testing, then device functionality can be tested, but defects and contamination risks increase
Solution Approach 1:
The intermediate layer is configured with localized openings only in regions where pad exposure is necessary for testing. The cover layer then protects all other areas, including exposed pads in the non-display region, from contamination while allowing electrical access where needed.
Solution Approach 2:
The intermediate layer is formed beforehand to provide a protective barrier over pads and underlying structures. This intermediate protection layer prevents contamination during subsequent fabrication steps, and the cover layer provides additional protection in final assembled devices.
Data Source
AI summary
Provided is a display device that includes a substrate including a plurality of pixels; a display element layer including a light emitting element provided in each of the pixels; and a touch sensor on the display element layer. The touch sensor may include: a base layer on the display element layer; a first conductive pattern on the base layer; a first insulating layer provided over the first conductive pattern; a second conductive pattern on the first insulating layer; a second insulating layer provided over the second conductive pattern; an intermediate layer on the base layer; and a cover layer provided over the intermediate layer. The intermediate layer and the cover layer may include different materials.