Color Filter Over-Coat Layer Light Leakage Prevention

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Solution Overview

Problem

In display devices, light leakage occurs due to gaps between light-emitting structures and their corresponding color filters, leading to unintended illumination of adjacent pixel areas and a decrease in image quality.

Innovation Solution

A display device design where a color filter is positioned between the lower substrate and the light-emitting structure, with an over-coat layer surrounding the color filter's side surface, and over penetrating holes filled by the color filter, ensuring the light emitted by each pixel area passes through the correct color filter, preventing leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a space is maintained between the light-emitting structure and the color filter, then the light-emitting structure can be properly positioned, but light leakage occurs and image quality decreases

Engineering Contradiction:

Improvepositioning accuracyVSAvoidlight leakage

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The color filter is embedded within the over-coat layer structure, with the over-coat layer forming a cavity that accommodates the color filter. This nested configuration allows the color filter to be positioned precisely while the over-coat layer fills and seals the surrounding space, preventing light leakage into adjacent pixels.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The over-coat layer acts as an intermediary substance between the light-emitting structure and the color filter. It fills the space that would otherwise allow light leakage, while maintaining the proper positioning of the color filter and enabling effective optical coupling.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If the color filter is disposed close to the substrate, then manufacturing is simplified, but light leakage occurs through gaps

Engineering Contradiction:

Improveassembly simplicityVSAvoidlight leakage

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The color filter is nested within the over-coat layer, which is itself disposed on the substrate. This integrated nested structure achieves both manufacturing simplicity (as a single assembly process) and effective light leakage prevention (through the space-filling over-coat layer).

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The invention merges the color filter and over-coat layer into a single integrated component assembly. The over-coat layer is formed to accommodate the color filter, combining positioning and light sealing functions into one manufactured unit, simplifying the overall manufacturing process.

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If the color filter and over-coat layer have different heights, then manufacturing flexibility is improved, but surface uniformity decreases

Engineering Contradiction:

Improvemanufacturing flexibilityVSAvoidsurface uniformity

Core Design Contradiction:

Adaptability or versatilityVSShape

Solution Approach 1:

The color filter is nested within the over-coat layer cavity, allowing the color filter to have a different height than the over-coat layer while maintaining a uniform upper surface. The over-coat layer extends beyond the color filter to provide a consistent top surface for subsequent manufacturing steps.

Inventive Principle:

Principle #7Nested doll (Nesting)

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

This configuration effectively prevents light leakage, ensuring that light from each pixel area is directed through the appropriate color filter, thereby enhancing image quality by maintaining accurate color representation and reducing unwanted illumination.

Implementation Method 1

The color filter may include a red color filter, a green color filter and a blue color filter corresponding to the first pixel area, the second pixel area and the third pixel area, respectively

Methodology Applied

Scientific EffectLight absorption and transmission: Absorption (EM radiation)

Implementation Method 2

a color filter is disposed between the lower substrate and the light-emitting structure

Methodology Applied

Scientific EffectOptical filtering: Filter (optical)

Data Source

PatentUS10411077B2Display device having a color filter

Publication Date: 2019.09.10 LG DISPLAY CO LTD

AI summary

A display device can include a lower substrate; a light-emitting structure including a lower electrode, a light-emitting layer, and an upper electrode, in which the lower electrode, the light-emitting layer and the upper electrode are sequentially stacked; a color filter disposed between the lower substrate and the light-emitting structure; and an over-coat layer surrounding a side surface of the color filter, in which an upper surface of the color filter facing the light-emitting structure is coplanar with an upper surface of the over-coat layer.