Blocking Layer Prevents Optical Adhesive Diffusion

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Solution Overview

Problem

In display device manufacturing, the edge portion of the adhesive layer between the display panel and the window diffuses due to applied pressure, leading to non-uniform thickness and gaps, which degrades display quality.

Innovation Solution

A blocking layer is introduced between the touch unit and the window, adjacent to the optical adhesive layer, with a thickness that increases with distance from the adhesive layer, forming a step structure to prevent the adhesive layer from diffusing and maintaining a constant interval between the display panel and the window.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If pressure is applied to attach the window to the display panel, then the bonding strength is improved, but the adhesive layer edge diffuses and thickness becomes non-uniform

Engineering Contradiction:

Improvebonding strengthVSAvoidadhesive layer thickness uniformity

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

A blocking layer is formed in advance at the edge region of the adhesive layer before the bonding process. This blocking layer prevents the adhesive from diffusing outward during the pressing operation, thereby maintaining uniform thickness while still allowing adequate bonding strength to be achieved through controlled pressure application.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The blocking layer is specifically positioned only at the edge regions where adhesive diffusion occurs, rather than uniformly across the entire adhesive area. This localized structure provides precise control over adhesive flow at critical areas while maintaining optimal bonding properties in the central regions.

Inventive Principle:

Principle #3Local quality

2Area of stationary object

If the adhesive layer edge diffuses, then the bonding area is increased, but the gap between display panel and window becomes non-uniform

Engineering Contradiction:

Improvebonding areaVSAvoidgap uniformity

Core Design Contradiction:

Area of stationary objectVSShape

Solution Approach 1:

The blocking layer is pre-formed at the adhesive edge regions to constrain the adhesive within a defined boundary during bonding. This prevents uncontrolled diffusion that would create non-uniform gaps, while still allowing sufficient adhesive coverage for effective bonding between the display panel and window.

Inventive Principle:

Principle #10Preliminary action

3Manufacturing precision

If a blocking layer is added to prevent adhesive diffusion, then the gap uniformity is improved, but the device complexity increases

Engineering Contradiction:

Improvegap uniformityVSAvoidstructure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The blocking layer is implemented only at the edge regions where adhesive diffusion control is needed, rather than as a complete circumferential structure. This localized approach achieves gap uniformity while minimizing the addition of structural complexity and material usage.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The blocking layer is divided into discrete segments positioned at specific edge regions rather than forming a continuous ring. This segmentation reduces the overall complexity of the structure while still providing effective control over adhesive diffusion at the critical areas where it occurs.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS11543910B2Display device with optical adhesive layer and blocking layer

Publication Date: 2023.01.03 SAMSUNG DISPLAY CO LTD

AI summary

A display device includes: a display panel; a touch unit that overlaps the display panel; a window that overlaps the display panel and the touch unit; an optical adhesive layer disposed between the touch unit and the window; and a blocking layer disposed between the touch unit and the window and next to the optical adhesive layer. The blocking layer has a thickness that increases with increasing distance from the optical adhesive layer.