AMOLED Subpixel Arrangement for High PPI Manufacturing

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Solution Overview

Problem

The existing AMOLED display technology faces challenges in achieving high pixel density due to the deformation of shadow masks during the high-temperature evaporation deposition process, leading to inaccuracies in subpixel positioning and limitations in pixel size and resolution.

Innovation Solution

A novel subpixel arrangement in a color display apparatus, where each pixel pair consists of five subpixels arranged symmetrically across two pixels, with specific length and width configurations, allowing for improved positioning accuracy and higher pixel density without deforming shadow masks, thereby enhancing the pixel per inch (PPI) threshold.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If shadow mask is used for evaporation deposition to form subpixels, then subpixel materials can be deposited by evaporation, but shadow mask deforms due to thermal expansion and gravity causing positioning inaccuracy

Engineering Contradiction:

Improvesubpixel positioning accuracyVSAvoidshadow mask stability

Core Design Contradiction:

Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The patent removes the shadow mask component from the manufacturing process entirely, replacing it with a direct evaporation deposition method where materials are deposited without a physical mask. This eliminates the source of deformation and positioning inaccuracy while maintaining the ability to form subpixel patterns through controlled material deposition.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical shadow mask system with a vapor-phase deposition system. Instead of using a physical mask that must be positioned and maintained mechanically, the invention uses evaporated materials that naturally conform to the substrate, eliminating mechanical positioning errors caused by thermal expansion and gravity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If shadow mask positioning accuracy is limited, then minimum pixel size threshold is created, but this limits pixel per inch (PPI) of the AMOLED

Engineering Contradiction:

Improvepixel per inch (PPI)VSAvoidpixel size control

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

By removing the shadow mask, the patent eliminates the minimum pixel size threshold that was imposed by mask positioning accuracy. This allows pixels to be made smaller without the risk of positioning errors, thereby enabling higher PPI displays to be manufactured.

Inventive Principle:

Principle #2Taking out (Extraction)

3Quantity of substance

If evaporation deposition is used as high temperature process, then subpixel materials can be deposited, but heat is generated causing shadow mask deformation

Engineering Contradiction:

Improvesubpixel material depositionVSAvoidprocess temperature

Core Design Contradiction:

Quantity of substanceVSTemperature

Solution Approach 1:

The patent removes the shadow mask from the high-temperature evaporation deposition process, allowing the process to proceed without the mask that would deform under thermal stress. This enables complete material deposition without compromising structural integrity.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent accepts the high temperature and heat generation as necessary for proper material deposition, and converts the potential harm (heat) into a benefit by ensuring complete and uniform material deposition without shadow mask interference. The heat is managed as a necessary condition for achieving high-quality subpixel formation.

Inventive Principle:

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

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 new subpixel arrangement increases the PPI threshold from 270 to 350, enabling higher resolution displays while maintaining the same pixel defining layer (PDL) requirements, thus overcoming the limitations of traditional AMOLED manufacturing.

Implementation Method 1

the subpixels may be manufactured by evaporation deposition using a shadow mask

Methodology Applied

Scientific EffectEvaporation deposition: Evaporation

Implementation Method 2

the shadow mask may deform during the manufacturing process due to thermal expansion and gravity

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS9262961B2Pixel arrangement of color display apparatus

Publication Date: 2016.02.16 AU OPTRONICS CORP

AI summary

A color display apparatus includes pixels P(i, j) arranged in a matrix having M columns and N rows, where i=1, 2, . . . , M, j=1, 2 . . . , N. A plurality of pixel pairs is defined along either the columns or the rows. Each pixel pair includes one pixel P(i, j) and the next immediate pixel, where if i is an odd integer, j is an odd integer, and if i is an even integer, j is an even integer. Each pixel pair has a first subpixel configured to display a first color and symmetrically positioned across the pixels, a pair of second subpixels configured to display a second color and symmetrically positioned in the pixels respectively, and a pair of third subpixels configured to display a third color and symmetrically positioned in the pixels respectively. The first subpixel is positioned between the pair of second subpixels.