Reverse Tapered Partition Structure for Display Luminance Efficiency

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Solution Overview

Problem

Display devices, particularly organic light emitting displays, face reduced luminance efficiency due to light being totally reflected toward the edge in mirror or transmission functions, which hinders the output of light emitted from the emission area.

Innovation Solution

A display panel with a reverse tapered partition structure on the second substrate, where the partitions have a lower refractive index than the material used for bonding, allowing light to be directed toward the second substrate without total reflection, thereby improving luminance efficiency and enabling light output from the emission area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a mirror function or transmission function is implemented in a display panel, then the display can reflect or transmit external light, but light emitted from pixels is totally reflected toward the edge, deteriorating luminance efficiency

Engineering Contradiction:
Improvemirror function or transmission functionVSAvoidluminance efficiency
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The display panel is divided into distinct functional regions: a pixel region for light emission and a non-pixel region containing reflective materials. Partitions separate these regions, directing light from pixels toward the viewer while preventing total reflection of emitted light toward the edges. This segmentation allows the panel to maintain both mirror/transmission functions and acceptable luminance efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the display panel are assigned different optical properties. The pixel region is optimized for light emission and viewing, while the non-pixel region contains reflective materials for mirror function. Partitions are positioned to create local optical guidance, directing light selectively based on location. This local differentiation resolves the contradiction by allowing each region to optimize its specific function without compromising overall performance.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If reflective materials are formed in the display panel to provide mirror function, then external light can be reflected, but light emitted from emission area is reflected toward the edge instead of being output

Engineering Contradiction:
Improvemirror functionVSAvoidlight reflection toward edge
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

Partitions are introduced as intermediary structures between the emission area and the reflective materials in the non-pixel region. These partitions act as optical mediators that guide light from the emission area toward the viewer while preventing it from reaching the reflective materials where it would be reflected toward the edge. This intermediary structure resolves the harmful effect of edge reflection while preserving the mirror function in the non-pixel region.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The problem of light reflection is addressed by adding a dimensional element - the partitions create a three-dimensional optical path structure. By positioning partitions at specific heights and angles, the optical path of emitted light is controlled in multiple dimensions, directing it toward the viewer while blocking paths that would lead to edge reflection. This dimensional approach separates the mirror function from the harmful reflection effect.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 reverse tapered partition structure enhances luminance efficiency by directing light emitted from the organic layer toward the second substrate, increasing the output efficiency of light without impairing visibility, and allows for adjustable viewing angles.

Implementation Method 1

the partitions have a lower refractive index than the material used for bonding, allowing light to be directed toward the second substrate without total reflection

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

allowing light to be directed toward the second substrate without total reflection

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP3185326B1Display panel with luminance efficiency improvement, display device, and method of fabricating the display panel
Publication Date: 2020.04.29 LG DISPLAY CO LTD
  • EP3185326B1 patent drawingFigure 1
  • EP3185326B1 patent drawingFigure 2
  • EP3185326B1 patent drawingFigure 3

AI summary

A display panel including a first substrate with pixel areas and emission areas which are defined by a plurality of gate lines and a plurality of data lines; and a second substrate on which partitions are formed in correspondence to the emission areas.