Pixel Isolation Structures for LED Crosstalk Reduction

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Solution Overview

Problem

Conventional methods for fabricating pixel structures with light-emitting diodes (LEDs) and photoluminescent regions require multiple deposition, patterning, and removal operations, reducing fabrication efficiency and leading to photoluminescent crosstalk between adjacent pixels.

Innovation Solution

The method involves depositing a light absorption material with photocurable and ultraviolet light absorbing compounds on a patterned LED substrate, curing it to form pixel isolation structures, and applying a directional isotropic light reflecting layer, which reduces the number of operations and minimizes crosstalk by allowing light to be directed into the photoluminescent regions while leaving top surfaces of LEDs uncoated.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional methods are used to form pixel isolation structures through multiple deposition, patterning, and removal operations, then the pixel structures can be fabricated, but the fabrication efficiency is reduced and photoluminescent crosstalk occurs between adjacent pixels

Engineering Contradiction:

Improvefabrication efficiencyVSAvoidphotoluminescent crosstalk

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent combines the pixel isolation structure formation and the light reflecting layer formation into a single isotropic layer deposition step. The isotropic layer serves dual functions: it forms the pixel isolation structures that prevent crosstalk and simultaneously creates the light reflecting surfaces that direct light into photoluminescent regions. This merging of functions eliminates multiple deposition, patterning, and removal operations, significantly improving fabrication efficiency while preventing photoluminescent crosstalk between adjacent pixels

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The isotropic layer is designed to perform multiple functions simultaneously: it acts as both the pixel isolation structure material and the light reflecting layer material. This multi-functional material approach eliminates the need for separate layers and operations, reducing fabrication complexity and improving productivity while maintaining the ability to prevent crosstalk and direct light effectively

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Manufacturing precision

If a directional isotropic light reflecting layer is applied, then light can be directed into photoluminescent regions while leaving LED top surfaces uncoated, but the deposition process must be precisely controlled

Engineering Contradiction:

Improvelight direction accuracyVSAvoiddeposition process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent utilizes changes in deposition parameters, specifically the angle of deposition, to achieve directional coverage. By controlling the deposition angle, the isotropic layer is deposited on specific surfaces (side walls and bottom surfaces of pixel isolation structures) while deliberately avoiding the top surfaces of LED structures. This parameter control enables precise light direction into photoluminescent regions without requiring complex deposition equipment or multiple processing steps

Inventive Principle:

Principle #35Parameter changes

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 approach significantly enhances fabrication efficiency and reduces photoluminescent crosstalk, improving the accuracy and brightness of displayed images by allowing more light to be directed into the photoluminescent regions and eliminating the need for additional removal operations.

Implementation Method 1

exposing a portion of the light absorption material to patterned light, wherein the patterned light cures the exposed portion of the light absorption material into pixel isolation structures

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

the light absorption material includes at least one photocurable compound and at least one ultraviolet light absorbing material

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 3

depositing an isotropic layer on a top portion and a side portion of the pixel isolation structures, where the LED structures are substantially free of the as-deposited isotropic light reflecting layer

Methodology Applied

Scientific EffectLight reflection: Reflection

Data Source

PatentUS20240096854A1Pixel isolation structures and methods of making them

Publication Date: 2024.03.21 APPLIED MATERIALS INC

AI summary

Processing methods are described that include forming a group of LED structures on a substrate layer to form a patterned LED substrate. The methods also include depositing a light absorption material on the pattered LED substrate, where the light absorption material includes at least one photocurable compound and at least one ultraviolet light absorbing material. The methods further include exposing a portion of the light absorption material to patterned light, wherein the patterned light cures the exposed portion of the light absorption material into pixel isolation structures. The methods additionally include depositing an isotropic layer on a top portion and a side portion of the pixel isolation structures, where the LED structures are substantially free of the as-deposited isotropic light reflecting layer.