OLED Filter Unit with Lens-Shaped Embossed Portions
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Solution Overview
Problem
Organic light emitting display devices experience reduced visibility and deteriorated viewing angles when exposed to external light due to light reflection, which existing solutions like polarizers cannot effectively address without compromising light extraction efficiency.
Innovation Solution
The implementation of a filter unit with a black matrix layer, organic layer featuring lens-shaped embossed portions, and color filters over a substrate with a pixel defining layer, which enhances light emission by controlling light exposure and improving refractive indices, thereby improving visibility and viewing angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a polarizer is used to reduce external light reflection, then visibility under external light is improved, but light extraction efficiency is compromised
Solution Approach 1:
The filter unit is divided into multiple functional layers: a black matrix layer for light absorption, an organic layer with lens-shaped embossed portions for light extraction enhancement, and color filters for wavelength selection. This segmentation allows each layer to perform its specific function optimally without the drawbacks of using a polarizer.
Solution Approach 2:
The organic layer incorporates lens-shaped embossed portions with curved surfaces that have different refractive indices. These curved structures enhance light extraction efficiency by manipulating light paths through refraction, while the black matrix layer simultaneously blocks external light reflection, resolving the contradiction between visibility and light extraction.
2Illumination intensity
If the refractive index of the organic layer is increased to improve light extraction, then viewing angle characteristic is improved, but manufacturing complexity increases
Solution Approach 1:
The patent specifies that the organic layer should have a refractive index of 1.7 or more to optimize light extraction efficiency and viewing angle characteristics. This parameter change is achieved by selecting appropriate organic materials during manufacturing, which balances performance improvement with manufacturing feasibility.
Solution Approach 2:
The lens-shaped embossed portions are formed by creating a mold pattern and replicating it across the entire display surface during the organic layer formation process. This copying approach allows complex curved structures to be manufactured efficiently through standard lithography and deposition techniques, avoiding excessive manufacturing complexity.
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 significantly enhances light extraction efficiency and viewing angle characteristics, improving visibility under external light conditions while simplifying the manufacturing process.
Implementation Method 1
The black matrix may have a light absorptive property
Implementation Method 2
Each of the lens-shaped embossed portions may have a convex-lens shape... A refractive index of the convex lens-shaped embossed portions may be about 1.7 or more
Data Source
AI summary
An organic light emitting display device including: a substrate; a plurality of first electrodes formed over the substrate; a pixel defining layer (PDL) formed over the substrate, and separating the plurality of first electrodes from one another when viewed in a thickness direction of the display device; a plurality of light emitting layer portions formed over one of the plurality of first electrodes; at least a second electrode formed over the plurality of light emitting layer portions; and a filter unit formed over the at least a second electrode. The filter unit includes a black matrix layer defining a plurality of openings, an organic layer formed over the black matrix layer and the plurality of openings, and comprising a plurality of lens-shaped embossed portions, and a plurality of color filters formed over the organic layer.