Display Device Reflection Preventing Layer Design
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Solution Overview
Problem
Organic light-emitting display devices face challenges in reducing external light reflection, which deteriorates light transmittance and picture quality, despite the use of polarizing plates, as metal patterns and layers reflect external light.
Innovation Solution
A display device design incorporating a substrate with pixel and non-pixel regions, featuring a semi-transmissive or reflecting second electrode in pixel regions and a thicker reflecting second electrode in non-pixel regions, along with a phase matching layer and light-absorbing layer in the reflection preventing layer, to manage light reflection and transmission effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a polarizing plate is used to reduce external light reflection, then reflection is reduced, but light transmittance deteriorates
Solution Approach 1:
The display device is divided into pixel regions and non-pixel regions, with different second electrode thicknesses in each region. The non-pixel region has a thicker second electrode that acts as a reflecting layer to reduce external light reflection, while the pixel region maintains a thinner semi-transmissive structure to preserve light transmittance and emission efficiency.
Solution Approach 2:
Different parts of the display device have different optical properties. The non-pixel region uses a thicker reflecting layer to block external light, while the pixel region uses a thinner semi-transmissive layer to allow light emission. This local differentiation resolves the contradiction between reducing reflection and maintaining transmittance.
2Object-affected harmful factors
If the second electrode thickness is increased to reduce external light reflection, then reflection is reduced, but light transmittance in pixel regions deteriorates
Solution Approach 1:
The second electrode is segmented into different thickness zones: a first thickness in pixel regions for light emission and a second greater thickness in non-pixel regions for reflection prevention. This segmentation allows each region to have optimized optical properties without compromising the other.
Solution Approach 2:
The second electrode exhibits local quality variation with different thicknesses in different regions. The pixel regions have thinner electrodes for transmittance while non-pixel regions have thicker electrodes for reflection reduction, resolving the contradiction through spatial differentiation.
3Reliability
If metal patterns and layers are used in the display device, then electrical conductivity and structure are improved, but external light reflection increases
Solution Approach 1:
The metal second electrode is configured with different thicknesses in different regions to achieve different optical functions while maintaining electrical conductivity. The non-pixel region's thicker metal layer provides reflection prevention, while the pixel region's thinner layer maintains both conductivity and light transmittance.
Solution Approach 2:
The thickness parameter of the second electrode is changed spatially to control optical properties. By varying the thickness from thin in pixel regions to thick in non-pixel regions, the device achieves both electrical conductivity and controlled light reflection/transmission characteristics.
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 design reduces external light reflection without additional planarizing plates, enhancing picture quality by controlling light reflection characteristics between pixel and non-pixel regions, thereby maintaining high transmittance and contrast.
Implementation Method 1
a phase matching layer, and at least one light-absorbing layer. The phase matching layer is arranged on the second electrode. The at least one light-absorbing layer is arranged on the phase matching layer
Implementation Method 2
The light-absorbing layer in a visible ray region may include a material in which multiplication of a refractive index and an extinction coefficient of the material is no less than 0.5
Implementation Method 3
The second electrode may be a semi-transmissive reflecting layer in the pixel regions. The second electrode may be a reflecting layer in the non-pixel region
Data Source
AI summary
A display device includes a substrate, a first electrode, an organic light-emitting layer, a second electrode, a phase matching layer, and at least one light-absorbing layer. The substrate includes a plurality of pixel regions and a non-pixel region. The non-pixel region is arranged between adjacent pixel regions. The first electrode is arranged in each pixel region. The organic light-emitting layer is arranged on the first electrode. The second electrode is arranged on the organic light-emitting layer. The phase matching layer is arranged on the second electrode. The at least one light-absorbing layer is arranged on the phase matching layer. A thickness of the second electrode in the non-pixel region is different than a thickness of the second electrode in the pixel regions.