Micro LED Display Redundancy for High Brightness and HDR

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Solution Overview

Problem

Existing organic electroluminescent display devices face limitations in manufacturing large-sized displays with high resolution and brightness, due to the use of metal shadow masks and the absorption of light by color filters in white OLEDs, which also affects color purity and image quality.

Innovation Solution

A micro LED display device with a redundancy micro LED system, where a second micro LED is used to enhance brightness and contrast ratio, and drive the display to prevent image degradation from defective pixels, allowing for HDR image representation by simultaneously driving both LEDs in specific areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a metal shadow mask is used to deposit organic luminescent layer, then the display device can be manufactured with conventional processes, but the device size cannot be increased and manufacturing resolution is limited

Engineering Contradiction:

Improvemanufacturing processVSAvoiddevice size

Core Design Contradiction:

Ease of manufactureVSArea of stationary object

Solution Approach 1:

The patent segments the luminescent layer deposition process by eliminating the metal shadow mask and using separate color sub-pixel structures (red, green, blue) that can be independently formed and assembled, enabling large-area manufacturing without resolution loss

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent transitions from planar shadow mask deposition to a multi-layered microcavity structure with bottom electrodes, reflective layers, and color filters arranged in vertical dimensions, allowing large-area fabrication with high resolution

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Productivity

If a white luminescent device with color filter is used, then the manufacturing process is simplified and yield is improved, but brightness is lowered due to light absorption by the color filter

Engineering Contradiction:

Improvemanufacturing yieldVSAvoidbrightness

Core Design Contradiction:

ProductivityVSIllumination intensity

Solution Approach 1:

The patent extracts the color filtering function from the white luminescent approach and implements direct color emission through separate red, green, and blue micro-LEDs or organic luminescent layers, eliminating light absorption losses while maintaining manufacturing simplicity

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies different luminescent materials and structures to different color sub-pixels (red, green, blue), with each having optimized microcavity structures and color filters specific to its wavelength, improving overall brightness and color purity

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If a white luminescent device with color filter is used, then manufacturing cost is reduced, but color purity is lowered due to light absorption by the color filter

Engineering Contradiction:

Improvemanufacturing costVSAvoidcolor purity

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent removes the color filter's light absorption function and replaces it with direct color emission from separate luminescent layers, achieving high color purity while maintaining the cost benefits of simplified manufacturing processes

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses composite structures combining organic luminescent materials with inorganic microcavity structures and color filters, optimizing both manufacturing cost and color purity through material synergies

Inventive Principle:

Principle #40Composite materials

4Device complexity

If a single LED per pixel is used, then the device structure is simple, but image quality degrades when pixels are defective

Engineering Contradiction:

Improvepixel structureVSAvoidimage quality

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent prepares backup sub-pixels in advance within each pixel structure, which can be activated through switching elements when the primary sub-pixels fail, preventing image quality degradation before it occurs

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent incorporates redundant sub-pixels and switching mechanisms as a cushioning measure against pixel failures, ensuring continuous reliable operation even when some sub-pixels become defective

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 micro LED display device achieves high brightness, long lifespan, and low unit costs, enabling the production of large-area displays with improved image quality and HDR representation, similar to real-world images by utilizing inorganic material LEDs and redundancy for defective pixels.

Implementation Method 1

a first micro LED and a second micro LED in each pixel area, wherein the first micro LED is configured to emit light to display an image

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS10580351B2Micro light-emitting diode display device and display device

Publication Date: 2020.03.03 LG DISPLAY CO LTD

AI summary

A micro LED display device includes a display panel. The display panel includes a plurality of pixel areas each having a thin film transistor. A first micro LED and a second micro LED are in each pixel area. The first micro LED is configured to emit light to display an image, and the second micro LED is configured to emit light to improve a displayed brightness for a specific area of the image.