Reflective Metal Layer for Micro-LED Luminance Efficiency

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Solution Overview

Problem

Micro-LED displays face degradation in display quality due to the light-emitting diodes' characteristic of emitting and diffusing light in multiple directions, which affects image clarity and luminance efficiency.

Innovation Solution

The implementation of a display device configuration that includes a substrate with a pixel circuit, an organic planarization film, a second electrode, a light-emitting element, and a metal layer, where the metal layer is strategically placed between the organic planarization film and the second electrode to reflect epi-illumination light towards the display surface, reducing leakage current and enhancing luminance efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If micro-LEDs are used for high definition and upsizing, then display resolution and size are improved, but light diffusion in multiple directions degrades display quality

Engineering Contradiction:

Improvedisplay resolutionVSAvoidlight diffusion

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

A reflective metal layer is introduced as an intermediary component between the light-emitting element and the encapsulation structure. This metal layer intercepts light that would otherwise diffuse in unwanted directions and redirects it toward the display surface, thereby maintaining high definition while controlling light diffusion patterns.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the harmful effect of light diffusion into a beneficial outcome by using the reflected light to enhance display brightness and uniformity. The metal layer captures light that would normally be lost through diffusion and redirects it to contribute to the overall display output, improving luminance efficiency.

Inventive Principle:

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

2Illumination intensity

If micro-LEDs emit light in multiple directions, then light output is increased, but image clarity and luminance efficiency are degraded

Engineering Contradiction:

Improvelight outputVSAvoidimage clarity

Core Design Contradiction:

Illumination intensityVSMeasurement precision

Solution Approach 1:

The metal layer serves as an optical intermediary that selectively redirects light paths. It maintains the high light output characteristic of micro-LEDs while filtering and redirecting the light distribution pattern to improve image clarity and luminance efficiency by concentrating light toward the intended display surface.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If epi-illumination light is not managed, then device structure is simpler, but leakage current increases and luminance efficiency decreases

Engineering Contradiction:

Improvestructure simplicityVSAvoidleakage current

Core Design Contradiction:

Device complexityVSLoss of energy

Solution Approach 1:

The metal layer acts as an intermediary that manages epi-illumination light by reflecting it toward the display surface. This prevents light from taking unwanted paths that would generate leakage current, thereby reducing energy loss while adding only a single structural layer to maintain relative simplicity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the potentially harmful epi-illumination light that would cause leakage current into a beneficial resource by reflecting it toward the display surface. This improves luminance efficiency while the single metal layer maintains structural simplicity.

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

This configuration effectively suppresses leakage current and improves luminance efficiency by reflecting epi-illumination light, thereby maintaining image clarity and reducing heat dissipation challenges associated with micro-LEDs.

Implementation Method 1

the metal layer is strategically placed between the organic planarization film and the second electrode to reflect epi-illumination light towards the display surface

Methodology Applied

Scientific EffectLight reflection: Reflection

Data Source

PatentUS20230197765A1Display device

Publication Date: 2023.06.22 MAGNOLIA WHITE CORP

AI summary

According to one embodiment, a display device includes an organic planarization film, a second electrode, a light emitting element and a metal layer. The organic planarization film is arranged on a substrate and covers a pixel circuit. The second electrode is electrically connected to a first electrode of the pixel circuit, in an area overlapping with a first contact hole formed in the organic planarization film, in planar view. The light emitting element is electrically connected to the second electrode. The metal layer is arranged between the organic planarization film and the second electrode. The metal layer is arranged on an entire surface of the organic planarization film, except for the area overlapping with the first contact hole in planar view.