OLED Lighting Apparatus with Microlens and Gas Venting
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Solution Overview
Problem
Organic light emitting diode (OLED) lighting apparatuses have low light extraction efficiency due to total reflection and absorption, leading to reduced luminance and shortened lifespan due to outgassing from the organic layer.
Innovation Solution
The OLED lighting apparatus includes a substrate with emitting and non-emitting areas, an auxiliary electrode, an overcoating layer with a microlens, and a gas blocking pattern to enhance light extraction and prevent outgassing, featuring a first electrode with open portions to release gases and a gas blocking pattern to prevent their reabsorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional OLED structure is used, then the device is simple to manufacture, but the light extraction efficiency is low due to total reflection and absorption
Solution Approach 1:
The device is divided into emitting areas and non-emitting areas, with the non-emitting areas serving as gas venting regions. This segmentation allows light to be extracted efficiently from the emitting areas while providing dedicated pathways for gas release in the non-emitting areas, resolving the contradiction between manufacturing simplicity and light extraction efficiency.
Solution Approach 2:
A buffer layer is introduced as an intermediary component between the substrate and the light emitting layer. This buffer layer serves dual functions: it facilitates light extraction by reducing total internal reflection at the substrate interface, and it provides gas venting pathways. The intermediary layer resolves the contradiction by adding a functional component that addresses both manufacturing considerations and optical performance.
2Illumination intensity
If high current is applied to increase luminance, then the brightness increases, but the lifetime is shortened due to outgassing
Solution Approach 1:
Gaseous compounds generated during operation are extracted from the device interior through the non-emitting areas that are in communication with the exterior environment. By removing the harmful gaseous byproducts that would otherwise accumulate and degrade the light emitting layer, the device can operate at high currents for extended periods, resolving the contradiction between luminance and lifetime.
Solution Approach 2:
The outgassing phenomenon, which is normally harmful to device lifetime, is converted into a beneficial process by designing the non-emitting areas as dedicated venting pathways. The gaseous compounds that would cause degradation are instead channeled out through controlled pathways, transforming a reliability issue into a feature that enables sustained high-luminance operation.
3Quantity of substance
If the organic layer is made thicker to improve light emission, then the light output increases, but outgassing worsens and reliability decreases
Solution Approach 1:
The problem of outgassing from a thicker organic layer is solved by introducing a vertical dimension for gas escape through the non-emitting areas. Instead of trying to manage gas accumulation within the horizontal plane of the thick organic layer, the design provides three-dimensional pathways extending from the organic layer through the buffer layer to the exterior, allowing gas to escape in the vertical dimension while maintaining thick organic emission layers.
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 improves light extraction efficiency and prevents the deterioration caused by outgassing, leading to increased luminance and extended lifespan of the OLED lighting apparatus.
Implementation Method 1
an overcoating layer in the emitting area on the substrate, the overcoating layer having a microlens including a plurality of convex portions and a plurality of concave portions
Implementation Method 2
a first electrode on the auxiliary electrode and the overcoating layer, the first electrode including at least one open portion exposing the overcoating layer in the second non-emitting area
Implementation Method 3
a gas blocking pattern covering the at least one open portion
Data Source
AI summary
An organic light emitting diode lighting apparatus can include a substrate having an emitting area and first and second non-emitting areas; an auxiliary electrode in the first non-emitting area on the substrate; an overcoating layer in the emitting area on the substrate, the overcoating layer having a microlens including a plurality of convex portions and a plurality of concave portions; a first electrode on the auxiliary electrode and the overcoating layer, the first electrode including at least one open portion exposing the overcoating layer in the second non-emitting area; a gas blocking pattern covering the at least one open portion; and a light emitting layer and a second electrode disposed on the first electrode and the gas blocking pattern.