Curved Black Matrix Sidewall for AMOLED Pixel Contamination

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Solution Overview

Problem

In the manufacturing of AMOLED displays with top emission structures, the thick black matrix with a slope angle between 30 to 60 degrees leads to splashing of color film droplets, causing contamination between adjacent pixels due to the larger droplet size required for micron-level thickness, which affects color saturation and display quality.

Innovation Solution

A display substrate with a black matrix having a concave curved surface is designed, utilizing a multi-layer insulating structure with varying etching rates and a negative photoresist material, along with an absorbing layer to prevent contamination by allowing droplets to return to their sub-pixel, and a blocking layer to protect the encapsulation layer during dry etching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the black matrix thickness is increased to ensure color saturation, then color saturation is improved, but droplet splashing between adjacent pixels occurs more frequently

Engineering Contradiction:

Improvecolor saturationVSAvoiddroplet splashing contamination

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies curvature by forming the sidewall of the black matrix as a concave curved surface rather than a straight vertical or sloped surface. This concave curvature causes splashed droplets to return to their original sub-pixel area instead of contaminating adjacent pixels, thereby maintaining color saturation while preventing contamination.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent changes the geometric parameters of the black matrix by forming a curved sidewall with specific radius of curvature (R1 and R2) instead of a linear profile. This parameter change in the sidewall shape modifies the trajectory of splashed droplets, causing them to return to the original pixel area and preventing cross-pixel contamination.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If a thick black matrix with slope angle of 30 to 60 degrees is used, then light shielding performance is improved, but droplet splashing in the direction of the slope causes contamination

Engineering Contradiction:

Improvelight shielding performanceVSAvoiddroplet splashing contamination

Core Design Contradiction:

Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the sloped linear profile with a concave curved profile for the black matrix sidewall. This curvature modification changes the direction of droplet movement upon contact, causing droplets to be redirected back toward the original pixel area rather than following the slope direction to adjacent pixels.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent converts the potentially harmful droplet splashing phenomenon into a beneficial effect by using the concave curved surface to redirect droplets back to their origin. The splashing that would normally cause contamination is now harnessed to return droplets to the correct pixel area, improving manufacturing yield.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Manufacturing precision

If the color film thickness is increased to micron level, then color saturation is improved, but droplet size increases leading to more splashing

Engineering Contradiction:

Improvecolor saturationVSAvoiddroplet splashing control

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent uses the concave curved sidewall of the black matrix to manage larger droplets formed during printing of thicker color films. The curvature geometry ensures that even larger droplets follow a trajectory that returns them to the original pixel area, maintaining color saturation without increasing contamination risk.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 concave curved sidewall of the black matrix effectively prevents droplet splashing between pixels, ensuring pure color and improved display quality by containing droplets within their respective sub-pixels, thus enhancing the yield and performance of the display substrate.

Implementation Method 1

a material of the black matrix includes a negative photoresist

Methodology Applied

Scientific EffectPhotoabsorption: Absorption (EM radiation)

Implementation Method 2

the first insulating layer, the second insulating layer and the third insulating layer are etched by a dry etching process

Methodology Applied

Scientific EffectPhysical vapor deposition: Plasma

Data Source

PatentUS9978995B2Display substrate having a black matrix with a curved surface, method for manufacturing the same and display device

Publication Date: 2018.05.22 BOE TECHNOLOGY GROUP CO LTD

AI summary

A display substrate having a black matrix with a curved surface, a method for manufacturing the same and a display device are provided. The display substrate includes a black matrix disposed between adjacent pixels, wherein a sidewall of the black matrix is a concave curved surface. During the formation of a color film, since the sidewall of the black matrix is formed as a concave curved surface, color film droplets in one sub-pixel may return into the sub-pixel along the curved surface while splashing to the sidewall of the black matrix, thereby the contamination to adjacent pixels caused by the droplets splashing may be avoided, and a yield of the substrate may be ensured.