OLED Anode Through-Holes for Light Extraction Efficiency
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Solution Overview
Problem
Conventional organic light-emitting diode (OLED) devices experience lower light extraction efficiency due to total reflection occurring between the air and glass layers, primarily because the refractive index of the anode layer is higher than that of the glass, leading to increased refraction angles and critical angle violations.
Innovation Solution
The OLED device incorporates a glass substrate, an anode layer with through holes, and a dielectric layer, where the refractive index of the anode layer is greater than the glass substrate, allowing light to pass through the holes and via in the dielectric layer directly to the glass substrate, reducing total reflection and enhancing light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If light is emitted from the organic light-emitting layer through the anode layer and glass layer, then the device structure is simple and易于制造, but total reflection occurs at the glass-air interface due to refractive index mismatch, resulting in low light extraction efficiency
Solution Approach 1:
The anode layer is segmented by introducing through-holes that divide the continuous anode structure into multiple regions. This segmentation allows light to escape through multiple paths (both through the through-holes and through the anode-glass interface), reducing the impact of total reflection at any single interface while maintaining the overall simplicity of the device structure.
Solution Approach 2:
The through-holes act as intermediary structures that provide an alternative light extraction path. By creating these intermediate openings, light can bypass the problematic glass-air interface where total reflection occurs, allowing direct extraction through the holes to the external environment, thus improving overall light extraction efficiency without complicating the basic device architecture.
2Reliability
If the refractive index of the anode layer is larger than the glass layer, then the anode layer can effectively transport holes, but the angle of refraction increases, causing total reflection at the glass-air interface
Solution Approach 1:
The through-holes segment the anode layer, creating multiple light extraction interfaces. Light that would otherwise be trapped by total reflection at the glass-air interface can now escape through the through-holes, which have different refractive index boundaries. This maintains the high refractive index anode material for reliable hole transport while providing alternative extraction paths that bypass the total reflection problem.
Solution Approach 2:
The invention adds a vertical dimension to light extraction by creating through-holes that extend from the top surface to the bottom surface of the anode layer. This dimensional change allows light to escape in multiple directions (through the holes and through the glass interface) rather than being constrained to a single planar interface, thereby improving light extraction efficiency without compromising hole transport performance.
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 improves light extraction efficiency by reducing the angle of refraction and preventing total reflection, thereby increasing the amount of light emitted from the OLED device.
Implementation Method 1
the refractive index of the anode layer is larger than the refractive index of the glass substrate, wherein a through hole is formed in the anode layer so that partial of the incident light from the organic layer can be extracted through the through hole to the glass substrate
Implementation Method 2
the refractive index of the dielectric layer is smaller than the refractive index of the organic layer, and a via is provided in the dielectric layer corresponding to the through hole, so that the partial of the light emitted from the organic layer can pass through the through hole, the via successively and directly to the glass substrate
Data Source
AI summary
The disclosure discloses a display apparatus and an organic light emitting diode device, wherein the organic light emitting diode device including a glass substrate, an anode layer, an organic layer and a cathode layer laminated sequentially, the refractive index of the anode layer is larger than the refractive index of the glass substrate, wherein a through hole is formed in the anode layer so that partial of the incident light from the organic layer can be extracted through the through hole to the glass substrate in order to reduce the total reflection phenomenon of the contracting surface of the anode layer and the glass substrate.